From b4b72320b621eae9268110a5fde76aa01cef6f37 Mon Sep 17 00:00:00 2001
From: Sascha Schulz <sschulz@dh-software.de>
Date: Do, 25 Mai 2023 11:11:25 +0200
Subject: [PATCH] add readme in plain txt format
---
index.html | 541 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 525 insertions(+), 16 deletions(-)
diff --git a/index.html b/index.html
index 8aa6001..88584f9 100644
--- a/index.html
+++ b/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>
@@ -1264,27 +1339,461 @@
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(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.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>
+ <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>
</div>
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