From 8822b0a6fde54910131ec48e0c09f720ee74d6f7 Mon Sep 17 00:00:00 2001 From: Sascha Schulz <sschulz@dh-software.de> Date: Do, 17 Aug 2023 16:49:06 +0200 Subject: [PATCH] Merge branch 'draft' --- index.html | 673 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 672 insertions(+), 1 deletions(-) diff --git a/index.html b/index.html index 92d3368..c224439 100644 --- a/index.html +++ b/index.html @@ -2125,6 +2125,677 @@ </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> @@ -2141,7 +2812,7 @@ hash: true, slideNumber: "c/t", transition: "fade", - + // Learn about plugins: https://revealjs.com/plugins/ plugins: [ RevealMarkdown, RevealHighlight, RevealNotes ] }); -- Gitblit v1.9.3