From 935b368767b1c0a665c5657c9c7815e71c36633d Mon Sep 17 00:00:00 2001
From: Sascha Schulz <sschulz@dh-software.de>
Date: Di, 15 Aug 2023 16:06:18 +0200
Subject: [PATCH] add strings, tagged strings, rest operator and relevant browser-APIs
---
index.html | 1401 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 1.399 insertions(+), 2 deletions(-)
diff --git a/index.html b/index.html
index 6f46a19..c224439 100644
--- a/index.html
+++ b/index.html
@@ -1317,6 +1317,9 @@
</pre>
</section>
<section>
+ <img data-src="/assets/images/constructor-and-its-prototype.svg">
+ </section>
+ <section>
<div>Dynamische Änderung des Prototypen</div>
<pre>
<code class="js" data-trim data-line-numbers>
@@ -1360,9 +1363,26 @@
</pre>
</section>
<section>
- <h3>Vererbung</h3>
+ <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() {
}
@@ -1370,18 +1390,22 @@
return "Shape";
}
+ // Unterklasse
function Rectangle(a, b) {
this.a = a;
this.b = 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";
}
@@ -1399,6 +1423,1379 @@
<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(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; // <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>
</div>
</div>
@@ -1415,7 +2812,7 @@
hash: true,
slideNumber: "c/t",
transition: "fade",
-
+
// Learn about plugins: https://revealjs.com/plugins/
plugins: [ RevealMarkdown, RevealHighlight, RevealNotes ]
});
--
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