Sascha Schulz
2023-09-12 a57a2f0bf32861c5389759f2fbe40a5d2b6b2950
index.html
@@ -959,9 +959,19 @@
                  <div><span class="fragment">Operator, </span><span class="fragment">Aufruf (Call), </span><span class="fragment">Ausdruck (Expression), </span><span class="fragment">Parameter, </span><span class="fragment">Argument, </span><span class="fragment">Literal, </span></div><div><span class="fragment">Zuweisung (Assignment), </span><span class="fragment">Linke Hand (Left hand), Rechte Hand (Right hand)</span></div>
               </section>
               <section>
                  <h3>Vorbereiten der Beispiele (bei Bedarf)</h3>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        # im Ordner 'examples/'
                        . hooks/post-checkout
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Ausführung</h3>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        # node [Script-Datei], z.B.
                        node index.js
                     </code>
                  </pre>
@@ -974,14 +984,7 @@
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Vorbereiten der Beispiele (bei Bedarf)</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        . hooks/post-checkout
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Variablen</h3>
                  <pre>
@@ -1098,6 +1101,55 @@
                  </pre>
               </section>
               <section>
                  <h3>Alternation</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        if (x == 1) {
                           // Code
                        }
                        else if (x == 2) {
                           // alternativer Code
                        }
                        else {
                           // Fallback
                        }
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Schleifen</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        for (let i = 0; i < 5; i++) {
                           // Code
                        }
                     </code>
                  </pre>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const a = [1, 2, 3];
                        for (const element of a) {
                           // Code
                        }
                     </code>
                  </pre>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        while (i == 1) {
                           // Code
                        }
                     </code>
                  </pre>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        do {
                           // Code
                        } while (i == 1)
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Arrays</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
@@ -1147,15 +1199,21 @@
                        let o = {};
                        
                        o.a = 1;
                        o["a"] = 1; // alternativ
                        
                        o["$ !"] = 2;
                        o["$ !"] = 2; // so sind auch komplexe Schlüssel möglich
                        // o."$ !" = 2; => Syntaxfehler
                        // o.$ ! = 2; => Syntaxfehler
                        o[true] = 3;
                        
                        console.log(Object.keys(o));
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        ['a', '$ !']
                        [ 'a', '$ !', 'true' ]
                     </code>
                  </pre>
               </section>
@@ -1202,6 +1260,13 @@
                        console.log(subtract(1, 2));
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        3
                        [Arguments] { '0': 1, '1': 2 }
                        -1
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Funktionen als Konstruktor</h3>
@@ -1232,6 +1297,7 @@
                           this.b = b;
                        }
                        
                        // jede Funktion besitzt einen Prototypen
                        Rectangle.prototype.getArea = function() {
                           return this.a * this.b;
                        }
@@ -1243,6 +1309,15 @@
                        console.log(r2.getArea());
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        6
                        20
                     </code>
                  </pre>
               </section>
               <section>
                  <img data-src="/assets/images/constructor-and-its-prototype.svg">
               </section>
               <section>
                  <div>Dynamische Änderung des Prototypen</div>
@@ -1264,25 +1339,1665 @@
                        console.log(r.getArea);
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        undefined
                        [Function (anonymous)]
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Aufgabe</h3>
                  Bringe dem Array eine Methode bei, welche die Summe aller enthaltenen Zahlen zurückgibt
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const a = [1, 2, 3];
                        console.log(a.sum());
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        6
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Lösung</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        Array.prototype.sum = function() {
                           let sum = 0;
                           for (let number of this) {
                              sum += number;
                           }
                           return sum;
                        }
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Vererbung</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers="1-13|15-18|20-29">
                        // Oberklasse
                        function Shape() {
                        }
                        Shape.prototype.getType = function() {
                           return "Shape";
                        }
                        // Unterklasse
                        function Rectangle(a, b) {
                           this.a = a;
                           this.b = b;
                           this.getCircumference = function() {
                              return 2 * a + 2 * b;
                           };
                        }
                        
                        Rectangle.prototype.getArea = function() {
                           return this.a * this.b;
                        // Prototype der Oberklasse in die Unterklasse kopieren
                        Rectangle.prototype = Object.create(Shape.prototype);
                        // Konstruktor der Oberklasse am Prototypen durch den eigenen ersetzen
                        Rectangle.prototype.constructor = Rectangle;
                        const r = new Rectangle(2, 3);
                        console.log(r.getType());
                        // .getType() selber implementieren
                        Rectangle.prototype.getType = function() {
                           return "Rectangle";
                        }
                        console.log(r.getType());
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        Shape
                        Rectangle
                     </code>
                  </pre>
               </section>
               <section>
                  <img data-src="/assets/images/inheritance-es5.svg">
               </section>
               <section>
                  <div>
                     <img width="800" height="500" data-src="/assets/images/mdn-prototype.jpg">
                  </div>
                  <p>
                     <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/push" style="font-size: 16px">https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/push</a>
                  </p>
               </section>
               <section>
                  <h3>Objektorientierung in es6</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        class Rectangle {
                           constructor(a, b) {
                              this.a = a;
                              this.b = b;
                           }
                           getArea() {
                              return this.a * this.b;
                           }
                        }
                        
                        const r = new Rectangle(2, 3);
                        
                        console.log(Object.keys(r));
                        console.log(r.getArea());
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        6
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Vererbung in es6</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers="1-6|8-16|18-27">
                        // Oberklasse
                        class Shape {
                           getType() {
                              return "Shape";
                           }
                        }
                        // Unterklasse erbt von Oberklasse
                        class Rectangle extends Shape {
                           constructor(a, b) {
                              super();
                              this.a = a;
                              this.b = b;
                           }
                        }
                        const r = new Rectangle(2, 3);
                        console.log(r.getType());
                        // Implementierung per Prototype weiterhin möglich, falls man so will
                        Rectangle.prototype.getType = function() {
                           return "Rectangle";
                        }
                        console.log(r.getType());
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        Shape
                        Rectangle
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Asynchronität</h3>
                  <p>Asynchron: Es wird nicht auf die Beendigung des Befehls gewartet, sondern mit dem Programm fortgefahren. Die Vollendung des asynchronen Befehls tritt <i style="font-style: italic">irgendwann</i> in der Zukunft ein.</p>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        setTimeout(callback, time); // Ausführung nach [time] Millisekunden
                        setInterval(callback, interval); // Ausführung alle [interval] Millisekunden
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        setTimeout(function() {
                           // Code, der nach 2 Sekunden ausgeführt wird
                           console.log("zweiter");
                        }, 2000);
                        console.log("erster");
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        erster
                        zweiter
                     </code>
                  </pre>
               </section>
               <section>
                  <p>Aufgabe: Schreibe ein Programm, das zwei weitere beliebige Texte mit jeweils 2 Sekunden Verzögerung von einander ausgibt, d.h.</p>
                  <p>"erster" -> 2s -> "zweiter" -> 2s -> "Text A" -> 2s -> "Text B"</p>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        setTimeout(function() {
                           console.log("zweiter");
                           // weiterer Code
                        }, 2000);
                        console.log("erster");
                     </code>
                  </pre>
               </section>
               <section>
                  Lösung: Callback-Hell oder Pyramide des Todes
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        setTimeout(function() {
                           console.log("zweiter");
                           setTimeout(function() {
                              console.log("Text A");
                              setTimeout(function() {
                                 console.log("Text B");
                              }, 2000);
                           }, 2000);
                        }, 2000);
                        console.log("erster");
                     </code>
                  </pre>
               </section>
               <section>
                  Hilfsmittel: Promises
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        new Promise(function (resolve, reject) {
                           // ich bin fertig
                           resolve();
                           // es ist ein Fehler aufgetreten
                           reject();
                        });
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const p = new Promise(function (resolve, reject) {...});
                        const p2 = new Promise(function (resolve, reject) {...});
                        const p3 = new Promise(function (resolve, reject) {...});
                        const p4 = new Promise(function (resolve, reject) {...});
                        p
                           .then(function() { return p2; })
                           .then(function() { return p3; })
                           .then(function() { return p4; });
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        console.log("erster");
                        delay(2000)
                           .then(function () {
                              console.log("zweiter");
                              return delay(2000);
                           })
                           .then(function() {
                              console.log("Text A");
                              return delay(2000);
                           })
                           .then(function() {
                              console.log("Text B");
                           })
                     </code>
                  </pre>
               </section>
               <section>
                  Aufgabe: Implementiere die Funktion "delay"
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const delay = function() {
                           // implementieren
                        }
                        console.log("erster");
                        delay(2000)
                           .then(function () {
                              console.log("zweiter");
                              return delay(2000);
                           })
                           .then(function() {
                              console.log("Text A");
                              return delay(2000);
                           })
                           .then(function() {
                              console.log("Text B");
                           })
                     </code>
                  </pre>
               </section>
               <section>
                  Lösung:
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const delay = function(ms) {
                           return new Promise(function(resolve, reject) {
                              setTimeout(function() {
                                 resolve();
                              }, ms);
                           });
                        }
                        console.log("erster");
                        delay(2000)
                           .then(function () {
                              console.log("zweiter");
                              return delay(2000);
                           })
                           .then(function() {
                              console.log("Text A");
                              return delay(2000);
                           })
                           .then(function() {
                              console.log("Text B");
                           })
                     </code>
                  </pre>
               </section>
               <section>
                  Rückgabewerte mit Promises
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const p = new Promise(function(resolve, reject) {
                           resolve("ok");
                        });
                        p.then(function(value) {
                           console.log(value);
                        });
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        ok
                     </code>
                  </pre>
               </section>
               <section>
                  Fehlerbehandlung mit Promises
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const p = new Promise(function(resolve, reject) {
                           reject(new Error("Fehler"));
                        });
                        p
                           .then(function() {
                              console.log("Ich werde nicht aufgerufen")
                           })
                           .catch(function(e) {
                              console.log(e.message);
                           });
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        Fehler
                     </code>
                  </pre>
               </section>
               <section>
                  Datei lesen mit NodeJS
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const fs = require("fs");
                        fs.readFile("./hello.txt", {encoding: "utf8"}, function(error, data) {
                           console.log(data);
                        });
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        Hello World!
                     </code>
                  </pre>
               </section>
               <section>
                  Aufgabe: "Promisifiziere" analog zu "delay" in der letzten Aufgabe den Aufruf von fs.readFile()
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const fs = require("fs");
                        function readFile() {
                           // implementieren
                        }
                        readFile("./hello.txt").then(function(content) {
                           console.log(content);
                        });
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        Hello World!
                     </code>
                  </pre>
               </section>
               <section>
                  Lösung:
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const fs = require("fs");
                        function readFile(path) {
                           return new Promise(function (resolve, reject) {
                              fs.readFile(path, {encoding: "utf8"}, function(error, data) {
                                 resolve(data);
                              });
                           });
                        }
                        readFile("./hello.txt").then(function(content) {
                           console.log(content);
                        });
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        Hello World!
                     </code>
                  </pre>
               </section>
               <section>
                  Aufgabe: Nutze die vorherige Lösung nun für eine Promise-Kette, sodass die Inhalte der zwei Dateien "hello.txt" und "hallo.txt" nacheinander ausgegeben werden:
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        Hello World!
                        Hallo Welt!
                     </code>
                  </pre>
               </section>
               <section>
                  Lösung:
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const fs = require("fs");
                        function readFile(path) {
                           return new Promise(function (resolve, reject) {
                              fs.readFile(path, {encoding: "utf8"}, function(error, data) {
                                 resolve(data);
                              });
                           });
                        }
                        readFile("./hello.txt")
                           .then(function(content) {
                              console.log(content);
                              return readFile("./hallo.txt");
                           })
                           .then(function(content) {
                              console.log(content);
                           });
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        Hello World!
                        Hallo Welt!
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Async - Await</h3>
                  <ul>
                     <li>Syntaktischer Zucker für Promises</li>
                     <li>Nutzung von <code>await</code> nur im Kontext einer <code>async</code>-Funktion möglich</li>
                  </ul>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        async function wrapper() {
                           const p = new Promise(function(resolve, reject) {
                              resolve("Hello from Promise!");
                           });
                           const result = await p;
                           console.log(result);
                        }
                        wrapper();
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        Hello from Promise!
                     </code>
                  </pre>
               </section>
               <section>
                  Aufgabe: Schreibe die Lösung der vorherigen Aufgabe nach Async - Await um
               </section>
               <section>
                  Lösung:
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const fs = require("fs");
                        function readFile(path) {
                           return new Promise(function (resolve, reject) {
                              fs.readFile(path, {encoding: "utf8"}, function(error, data) {
                                 resolve(data);
                              });
                           });
                        }
                        async function wrapper() {
                           const content1 = await readFile("./hello.txt");
                           const content2 = await readFile("./hallo.txt");
                           console.log(content1);
                           console.log(content2);
                        }
                        wrapper();
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        Hello World!
                        Hallo Welt!
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Destructuring</h3>
                  <p>Auflösen von komplexen Strukturen</p>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        // Objekt destrukturieren (per Attribut-Namen)
                        const { a, b } = { a: 1, b: 2 };
                        console.log(a);
                        console.log(b);
                        // Array destrukturieren (per Position)
                        const [ c, d ] = [3, 4];
                        console.log(c);
                        console.log(d);
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        1
                        2
                        3
                        4
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        // Bei Objekten Elemente umbenennen oder auch auslassen
                        const { a: x, b: y } = { a: 1, b: 2, c: 3 };
                        console.log(x);
                        console.log(y);
                        // Bei Arrays Elemente auslassen
                        const [ , a, b, , c] = [3, 4, 5, 6, 7, 8];
                        console.log(a);
                        console.log(b);
                        console.log(c);
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        1
                        2
                        4
                        5
                        7
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        // Verschachteltes Destructuring
                        const {a: [, x, ] } = { a: [0, 1, 2]};
                        console.log(x);
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        1
                     </code>
                  </pre>
               </section>
               <section>
                  Aufgabe: x soll die 5 enthalten
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const o = { a: [0, {b: [0, 5]}, 2]};
                        const  { /* Destructuring-Ausdruck */ } = o;
                        console.log(x);
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        5
                     </code>
                  </pre>
               </section>
               <section>
                  Lösung:
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const o = { a: [0, { b: [0, 5] }, 2]};
                        const { a: [, { b: [, x] }]} = o;
                        console.log(x);
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        5
                     </code>
                  </pre>
               </section>
               <section>
                  Aufgabe: x soll die 3 enthalten
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const o = { a: [0, {b: [0, { c: [{ x: 5 }, { d: 3}] }]}, 2]};
                        const  { /* Destructuring-Ausdruck */ } = o;
                        console.log(x);
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        3
                     </code>
                  </pre>
               </section>
               <section>
                  Lösung:
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const o = { a: [0, {b: [0, { c: [{ x: 5 }, { d: 3}] }]}, 2]};
                        const  { a: [, {b: [, { c: [, { d: x}] }] }] } = o;
                        console.log(x);
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        3
                     </code>
                  </pre>
               </section>
               <section>
                  <p>Destructuring zum parallelen Ausführen von mehreren Promises</p>
                  <pre>
                     <code class="js" data-trim data-line-numbers="1-10|11-21">
                        const fs = require("fs");
                        function readFile(path) {
                           return new Promise(function (resolve, reject) {
                              fs.readFile(path, {encoding: "utf8"}, function(error, data) {
                                 resolve(data);
                              });
                           });
                        }
                        async function wrapper() {
                           const [ content1, content2 ] = await Promise.all([
                              readFile("./hello.txt"),
                              readFile("./hallo.txt")
                           ]);
                           console.log(content1);
                           console.log(content2);
                        }
                        wrapper();
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Try-Catch-Finally</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        function throwError() {
                           try {
                              throw new Error("Fehler!");
                              return "Hello World!";
                           }
                           catch (e) {
                              return e.message;
                           }
                           finally {
                              console.log("Finally wird immer ausgeführt");
                              return "Finally!";
                           }
                        }
                        const result = throwError();
                        console.log(result);
                     </code>
                  </pre>
                  <pre class="fragment">
                     <code class="bash" data-trim data-line-numbers>
                        Finally wird immer ausgeführt
                        Finally!
                     </code>
                  </pre>
               </section>
               <section>
                  <p>Anwendungsbeispiel für Try-Catch-Finally</p>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        function readFromDatabase() {
                           try {
                              db.connect();
                              return db.read();
                           }
                           catch (e) {
                              console.log(e.stack);
                              return "";
                           }
                           finally {
                              if (db.open) {
                                 db.close();
                              }
                           }
                        }
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Scope</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        function a() {
                           const x = 5;
                           return function() {
                              return x * x;
                           };
                        }
                        const squareX = a();
                        const result = squareX();
                        console.log(result);
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        25
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>this</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        class MyClass {
                           constructor(a) {
                              this.a = a;
                           }
                           getA() {
                              return this.a;
                           }
                        }
                        const x = new MyClass(5);
                        const y = new MyClass(10);
                        console.log(x.getA());
                        console.log(y.getA());
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        5
                        10
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        global.a = 5;
                        function foo() {
                           this.a += 10;
                        }
                        foo();
                        console.log(a);
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        15
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        class MyClass {
                           /* ... */
                           setA() {
                              function f() {
                                 this.a += 100;
                              }
                              f();
                           }
                        }
                        const x = new MyClass(5);
                        x.setA();
                        console.log(x.getA());
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        TypeError: Cannot read property 'a' of undefined
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        class MyClass {
                           /* ... */
                           setA() {
                              const me = this;
                              function f() {
                                 me.a += 100;
                              }
                              f();
                           }
                        }
                        const x = new MyClass(5);
                        x.setA();
                        console.log(x.getA());
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        105
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Arrow-Funktionen</h3>
                  <ul>
                     <li>Kompakte Schreibweise einer normalen Funktion</li>
                     <li>Bei Einzeilern ist das <code>return</code> nicht notwendig</li>
                     <li>this-Pointer des aktuellen Kontextes wird beibehalten</li>
                  </ul>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        // Einzeiler
                        const f1 = _ => 1;
                        const f2 = () => 1;
                        const f3 = (x) => x * x;
                        const f4 = (x, y) => x + y;
                        // Mehrzeiler
                        const f5 = (x, y) => {
                           return x * y;
                        };
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        class MyClass {
                           /* ... */
                           setA() {
                              const f = () => {
                                 this.a += 100;
                              }
                              f();
                           }
                        }
                        const x = new MyClass(5);
                        x.setA();
                        console.log(x.getA());
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        105
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Generator-Funktionen</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        function* generator() {
                           let i = 0;
                           while(true) {
                              yield i;
                              i++;
                           }
                        }
                        const g = generator();
                        console.log(g.next().value);
                        console.log(g.next().value);
                        console.log(g.next().value);
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        1
                        2
                        3
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Generator-Funktionen</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        function* generator() {
                           yield 1;
                           yield 2;
                           yield 3;
                        }
                        const g = generator();
                        for (const i of g) {
                           console.log(i);
                        }
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        1
                        2
                        3
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Nützliche Array-Funktionen</h3>
               </section>
               <section>
                  Aufgabe: Schreibe ein Programm, das den Gesamtumsatz aus dem ersten Halbjahr berechnet
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const revenues = [
                           {month: 0, revenue: 1000},
                           {month: 1, revenue: 2000},
                           {month: 2, revenue: 3000},
                           {month: 3, revenue: 4000},
                           {month: 4, revenue: 5000},
                           {month: 5, revenue: 6000},
                           {month: 6, revenue: 6000},
                           {month: 7, revenue: 5000},
                           {month: 8, revenue: 4000},
                           {month: 9, revenue: 3000},
                           {month: 10, revenue: 2000},
                           {month: 11, revenue: 1000}
                        ];
                        let totalRevenue = 0;
                        /* ... */
                        console.log(totalRevenue);
                     </code>
                  </pre>
               </section>
               <section>
                  Lösung
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        totalRevenue = revenues
                           .filter((revenue) => revenue.month < 6)
                           .map((revenue) => revenue.amount)
                           .reduce((sum, amount) => sum + amount, 0);
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        21000
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
                        a.filter((e) => e > 2); // Filterung
                        a.map((e) => e * 2); // Umformung
                        a.reduce((p, e) => p + e, 0); // Zusammenrechnung / Reduzierung
                        a.some((e) => e > 5); // true wenn min. ein Element die Bedingung erfüllt
                        a.every((e) => e > 5); // true wenn alle Elemente die Bedingung erfüllen
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Map</h3>
                  <ul>
                     <li>auch als "assoziatives Array" bezeichnet</li>
                     <li>iterierbare Liste</li>
                     <li>ideal zur Assoziation von z.B. Hashes zu Objekt-Instanzen o.ä.</li>
                     <li>nutzbar ab es6 / es2015</li>
                     <li>löst herkömmliche Objekte als Hash-Map ab</li>
                  </ul>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const m = new Map();
                        m.set("a", 0);
                        m.set("a", 1);
                        m.set("b", 2);
                        m.has("c"); // => false
                        m.delete("b");
                        console.log(m.get("a")); // => 1
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        m.forEach((k, v) => console.log(k, v)) // => "a" 1 ...
                        for (const entry of m.entries()) {
                           console.log(entry); // => ["a", 1] ...
                        }
                        for (const key of m.keys()) {
                           console.log(key); // => "a" ...
                        }
                        for (const value of m.values()) {
                           console.log(value); // => "1" ...
                        }
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Set</h3>
                  <ul>
                     <li>enthält nur einzigartige Werte</li>
                     <li>iterierbare Liste</li>
                     <li>ideale Struktur, wenn einzelne Werte einzigartig sein sollen</li>
                     <li>nutzbar ab es6 / es2015</li>
                     <li>löst individuelle Lösungen mittels Arrays und Array.prototype.indexOf o.ä. ab</li>
                  </ul>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const s = new Set();
                        s.add("a");
                        s.add("a");
                        s.has("c"); // => false
                        s.delete("a");
                        console.log(s.size); // => 0
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        s.forEach((k, v) => console.log(k, v)) // => "a" "a" ...
                        for (const entry of m.entries()) {
                           console.log(entry); // => ["a", "a"] ...
                        }
                        for (const key of m.keys()) {
                           console.log(key); // => "a"...
                        }
                        for (const value of s.values()) {
                           console.log(value); // => "a" ...
                        }
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>DOM-Events</h3>
                  <ul>
                     <li>funktionale Ausführung von Code</li>
                     <li>Trigger können Klicks, Scrollen, Tastendrücke, Änderungen der Fenstergröße usw. sein</li>
                  </ul>
               </section>
               <section>
                  <img data-src="/assets/images/dom-events.svg">
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        function doSomething(e) {
                           console.log("capture");
                        }
                        function click(e) {
                           console.log("bubble");
                        }
                        div.addEventListener("click", doSomething, true);
                        button.addEventListener("click", click, false /* default */);
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        capturing
                        bubble
                     </code>
                  </pre>
               </section>
               <section>
                  <p>Aufgabe: Erweitere das vorherige Beispiel so, dass das div-Element einen weiteren Click-Handler bekommt,
                  der den Text "bubble2" anzeigt, nachdem "bubble" in der Konsole geloggt wurde.</p>
                  <p>Erwartete Ausgabe:</p>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        capturing
                        bubble
                        bubble2
                     </code>
                  </pre>
               </section>
               <section>
                  <p>Lösung:</p>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        function doSomething(e) {
                           console.log("capture");
                        }
                        // neu
                        function doSomething2(e) {
                           console.log("bubble2");
                        }
                        function click(e) {
                           console.log("bubble");
                        }
                        div.addEventListener("click", doSomething, true);
                        div.addEventListener("click", doSomething2, false); // neu
                        button.addEventListener("click", click, false /* default */);
                     </code>
                  </pre>
               </section>
               <section>
                  Die Bubble-Phase stoppen
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        function click(e) {
                           e.stopPropagation()
                        }
                     </code>
                  </pre>
               </section>
               <section>
                  <p>Aufgabe: Ändere das Ergebnis des vorherigen Beispiels, sodass die Bubble-Phase auf Ebene des button-Elements gestoppt wird. Was ändert sich in der Ausgabe?</p>
               </section>
               <section>
                  <p>Lösung:</p>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        function doSomething(e) {
                           console.log("capture");
                        }
                        function doSomething2(e) {
                           console.log("bubble2");
                        }
                        function click(e) {
                           e.stopPropagation();
                           console.log("bubble");
                        }
                        div.addEventListener("click", doSomething, true);
                        div.addEventListener("click", doSomething2, false);
                        button.addEventListener("click", click, false /* default */);
                     </code>
                  </pre>
               </section>
               <section>
                  Events programatisch triggern:
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        button.dispatchEvent(new Event("click"));
                     </code>
                  </pre>
               </section>
               <section>
                  Events sind synchron:
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        doSomethingElse();
                        button.dispatchEvent(new Event("click"));
                        doAnotherThing(); // wird erst ausgeführt, wenn zuvor alle Event-Handler fertig sind
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Strings</h3>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const empty1 = "";
                        const empty1 = '';
                        const s1 = 'abc';
                        const s2 = "abc";
                        const s3 = 'a"b"c';
                        const s4 = "a\"b\"c";
                        const s5 = 'a\'b\'c';
                        const s6 = "a'b'c";
                        const s7 = `a'b'"c"`;
                     </code>
                  </pre>
               </section>
               <section>
                  <h5>Strings zusammenfügen</h5>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const age = 10;
                        // Konkatenation
                        const s = "My age is " + number + "!";
                        // Interpolation
                        const s = `My age is ${number}!`;
                        // => "My age is 10!"
                     </code>
                  </pre>
               </section>
               <section>
                  <h5>Template Strings</h5>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        function sayHello() {
                           return "Hello";
                        }
                        let interpolation = `${sayHello()}`;
                        // => "Hello"
                        interpolation = `5 + 5 = ${5+5}`;
                        // => "5 + 5 = 10"
                     </code>
                  </pre>
               </section>
               <section>
                  lit
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        return html`<div>hello world!</div>`
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        function myTag() {
                           console.log(arguments);
                           // return 5;
                           // return true;
                           return "abc";
                        }
                        let interpolation = myTag`a ${5} b ${6} c`;
                        // => "abc"
                     </code>
                  </pre>
                  <pre>
                     <code class="bash" data-trim data-line-numbers>
                        Arguments(3) [Array(3), 5, 6]
                           0 : (3) ['a ', ' b ', ' c', raw: Array(3)]
                           1 : 5
                           2 : 6
                     </code>
                  </pre>
               </section>
               <section>
                  <h5>Aufgabe</h5>
                  <p>Schreibe ein Tag, welches die Zahlen aus den dynamischen Ausdrücken zusammenrechnet (<code>strings.js</code>)</p>
               </section>
               <section>
                  <h5>Lösung</h5>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        function add(parts, ...numbers) {
                           return numbers.reduce((p, c) => p + c, 0);
                        }
                        let sum = add`a ${5} b ${6} c`;
                        console.log(sum);
                        // => 11
                     </code>
                  </pre>
               </section>
               <section>
                  <h5>Rest-Operator</h5>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        function add(...numbers) {
                           return numbers.reduce((p, c) => p + c, 0);
                        }
                        add(1, 2, 3); // => 6
                     </code>
                  </pre>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const o1 = {a: 1, b: 2};
                        const o2 = {x: 5, y: 6, ...o1};
                     </code>
                  </pre>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        const a1 = [4, 5, 6];
                        const a2 = [1, 2, 3, ...a1];
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Relevante Browser-APIs</h3>
               </section>
               <section>
                  <h5>window</h5>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        window.innerWidth; // innere Auflösung des sichtbaren Fensters
                        window.innerHeight;
                        window.outerWidth; // äußere Auflösung des Browserfensters inklusive Adresszeile usw.
                        window.outerHeight;
                        window.addEventListener(); // Events an das äußerste "Dach"-Element hängen
                     </code>
                  </pre>
               </section>
               <section>
                  <h5>location</h5>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        location.href; // aktuelle URL
                        location.host; // aktuelle Domain, z.B. "www.google.de"
                        location.protocol; // aktuelles Protokoll, z.B. "https:"
                     </code>
                  </pre>
               </section>
               <section>
                  <h5>Navigator</h5>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        navigator.language; // bevorzugte Browsersprache, z.B. "de"
                        navigator.userAgent; // z.B. "Mozilla/5.0 (Linux; Android 6.0; Nexus 5 Build/MRA58N) [...]"
                        navigator
                           .mediaDevices
                           .getDisplayMedia(); // Fordere Erlaubis zum Streamen von Anwendungen oder Bildschirmen an
                     </code>
                  </pre>
               </section>
               <section>
                  <h5>Document</h5>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        document.body; // &lt;body>-Element der Seite
                        document.activeElement; // aktives Element der Seite, welche gerade den Fokus besitzt
                        document.cookie; // für die aktuelle Seite gesetzte Cookies
                        document.execCommand("copy"); // Texte in die Zwischenablage zu schreiben
                        document.createElement("div"); // erzeuge neues DOM-Element mit angegebenen Tag
                     </code>
                  </pre>
               </section>
               <section>
                  <h5>LocalStorage</h5>
                  <pre>
                     <code class="js" data-trim data-line-numbers>
                        // auf 5MB Daten pro Domain begrenzt
                        localStorage.getItem(key); // Element holen
                        localStorage.setItem(key, value); // Element setzen
                        localStorage.removeItem(key); // Element entfernen
                     </code>
                  </pre>
               </section>
            </section>
            <section>
               <section>
                  <h2>CSS</h2>
                  <img data-src="/assets/images/css-sucks.png">
               </section>
               <section>
                  <h3>Warum CSS?</h3>
                  <ul>
                     <li>Erhöhte Zugänglichkeit des Inhalts</li>
                     <li>Wiederverwendbarkeit</li>
                  </ul>
               </section>
               <section>
                  <h3>Syntax</h3>
                  <pre>
                     <code class="css" data-trim data-line-numbers>
                        selector [, selector2, selector3, ...] {
                           property1: value;
                           property2: value;
                        }
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Beispiel</h3>
                  <pre>
                     <code class="css" data-trim data-line-numbers>
                        html, body {
                           width: 100%;
                           height: 100%;
                           margin: 0;
                        }
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Selektoren</h3>
                  <pre>
                     <code class="css" data-trim data-line-numbers>
                        /* Elemente */
                        html, body {...}
                        /* IDs */
                        #my-id {...}
                        /* Klassen */
                        .my-class {...}
                        /* Pseudo-Klassen */
                        div:hover {...}
                        /* Attribute */
                        div[my-attribut="abc"] {...}
                        /* Kombinationen */
                        div.my-class#my-id {...}
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Variablen</h3>
                  <pre>
                     <code class="css" data-trim data-line-numbers>
                        html {
                           --my-background-color: #abcdef;
                        }
                        html div {
                           background-color: var(--my-background-color, white);
                        }
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Das <code>display</code>-Attribut</h3>
               </section>
               <section>
                  <p>block</p>
                  <img data-src="/assets/images/css-display-block.svg">
                  <ul>
                     <li>untereinander angeordnet</li>
                     <li>nehmen sich die volle Breite</li>
                     <li><code>width</code> und <code>height</code> möglich</li>
                  </ul>
               </section>
               <section>
                  <p>inline</p>
                  <img data-src="/assets/images/css-display-inline.svg">
                  <ul>
                     <li>Standard bei <code>Custom Elements</code></li>
                     <li>nur so groß wie der content</li>
                     <li><code>width</code> und <code>height</code> nicht möglich</li>
                     <li>nebeneinander angeordnet</li>
                  </ul>
               </section>
               <section>
                  <p>inline-block</p>
                  <img data-src="/assets/images/css-display-inline-block.svg">
                  <ul>
                     <li>Mischform von <code>block</code> und <code>inline</code></li>
                     <li>nur so groß wie der content</li>
                     <li><code>width</code> und <code>height</code> möglich</li>
                     <li>nebeneinander angeordnet</li>
                  </ul>
               </section>
               <section>
                  <h3>Das <code>position</code>-Attribut</h3>
               </section>
               <section>
                  <p>static</p>
                  <img data-src="/assets/images/css-position-static.svg">
                  <ul>
                     <li>Standard</li>
                     <li>Element wird am Ort der Verankerung im HTML dargestellt</li>
                  </ul>
               </section>
               <section>
                  <p>relative</p>
                  <img data-src="/assets/images/css-position-relative.svg">
                  <ul>
                     <li>Verschiebung zur eigentlichen <code>static</code>-Position, z.B. mittels <code>left: 20px</code></li>
                  </ul>
               </section>
               <section>
                  <p>absolut</p>
                  <img data-src="/assets/images/css-position-absolute.svg">
                  <ul>
                     <li>relative Verschiebung zum nächsten nicht-<code>static</code>-Parent (sonst <code>window</code>)</li>
                  </ul>
               </section>
               <section>
                  <h3>Aufgabe</h3>
                  <p>Implementiere folgendes Beispiel-Menü</p>
                  <iframe data-src="/assets/html/css-menu.html"></iframe>
               </section>
               <section>
                  <h3>Lösung</h3>
                  <pre>
                     <code class="css" data-trim data-line-numbers>
                        .menu-item {
                           display: inline-block;
                           position: relative;
                        }
                        .menu-item .children {
                           display: none;
                           position: absolute;
                        }
                        .menu-item:hover .children {
                           display: block;
                        }
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="html" data-trim data-line-numbers>
                        <script type="text/template">
                           <div class="menu">
                              <div class="menu-item">Eins</div>
                              <div class="menu-item">
                                 Hover Me!
                                 <div class="children">
                                    <div>Item 1</div>
                                    <div>Item 2</div>
                                 </div>
                              </div>
                              <div class="menu-item">Drei</div>
                           </div>
                        </script>
                     </code>
                  </pre>
               </section>
               <section>
                  <h3>Viewport</h3>
                  <pre>
                     <code class="html" data-trim data-line-numbers>
                        &lt;!DOCTYPE html>
                        &lt;html>
                           &lt;head>
                              &lt;meta charset="utf-8">&lt;/meta>
                              &lt;meta
                                 name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no"
                              >
                           &lt;/head>
                           &lt;body>
                              ...
                           &lt;/body>
                        &lt;/html>
                     </code>
                  </pre>
               </section>
               <section>
                  <pre>
                     <code class="bash" data-trim data-line-numbers="">
                        npm install -g http-server
                        cd pfad/zum/projekt
                        http-server --port 8080
                     </code>
                  </pre>
               </section>
@@ -1302,7 +3017,7 @@
            hash: true,
            slideNumber: "c/t",
            transition: "fade",
            // Learn about plugins: https://revealjs.com/plugins/
            plugins: [ RevealMarkdown, RevealHighlight, RevealNotes ]
         });