TypeScript: Unterschied zwischen den Versionen
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Zeile 132: | Zeile 132: | ||
= Operatoren = | = Operatoren = | ||
== instanceof == | |||
<syntaxhighlight lang="ts"> | |||
if (element instanceof HTMLElement){ | |||
doIt(); | |||
} | |||
</syntaxhighlight> | |||
== spread-Operator == | == spread-Operator == | ||
<syntaxhighlight lang="ts"> | <syntaxhighlight lang="ts"> |
Version vom 29. Mai 2022, 10:00 Uhr
Links
Konstanten, Variablen
- 'var'-Variablen sind global, 'let'-Variablen sind lokal (blockgebunden).
const E_DISK: string = 'disk error';
var globalLastMessage: string = 'Error';
for (let i=0; i < 4; i++){}
const myArray = [ 0, 'string', { firstname: 'Joe' } ];
const onlyNumbers: number[] = [ 1, 2, 3];
let arg: any = 5; ... arg = 'string';
let width, height: number;
let rest: number[];
const [width, height] = [1, 2];
const [width, ...rest] = [1, 2, 3, 4]; // rest hat den Wert [2, 3, 4]
Statements
for (let i = 0; i < 3; i++){
doit(i);
}
let arr = [10, 20, 30, 40];
// for in loops over enumerable property names of an object.
// Loops over keys:
for (var val in arr) {
doit(val);
}
// for of (new in ES6) does use an object-specific iterator and loops over the values generated by that.
// Loops over values:
for (var val in iterator) {
doit(val);
}
Typen
String
let x ='Hi';
x = `2 lines:
Say: ${x}
`;
Number
Array
let a: string[]; a.push('Hi'); a[0] = 'Hello'; a[1] = 'world'; let b = [12.4, 100, -33.4]; let len = b.length; let series = [1, 2, 3]; var series2 = series.concat(47, 49); var index = series2.indexOf(47); // forEach(), map(), reduce(), and filter() let doubleIt = series.map(e => e* 2); let scores : (string | number)[]; scores = ['Programming', 5, 'Software Design', 4];
- Assoziatives Array:
var information = new Array(); information["key1"] = 25; const array1 = { “one”: 1, “two”: 2, “three”: 3 }; const iterator = array1.keys(); for (const key of iterator) { console.log(key); }
Any
Enums
typedef Status = 'active' | 'inactive';
Funktionen/Methoden
# default parameters: getList(offset: number=0, count: number=20){ ... }
Klassen
- Nur ein Konstruktor
class User {
publicItems: string;
private privateMember: string = 'secret';
private privateNumber = 25; // impliziter Typ.
constructor(items: string){
this.privateItems = items;
}
append(item: string): string { this.publicItems += ';' + item; return this.publicItems; }
// getter + setter:
get currentNumber(): number { return this.privateNumber; }
set number(value: number): void { this.privateNumber = value; }
add(inc: number) => return privateNumber + number;
printAll(...args): void {
print(args[0] + ': ' + args);
}
}
class SuperUser extends User {
constructor(items: string){
super(items);
}
}
Interfaces
interface Contact {
firstname: string;
lastname: string;
}
const contact: Contact = {
firstname: 'Joe',
lastname: 'Doo'
}
class Address implements Contact {
firstname = 'Eve';
lastname = 'Smith';
}
Operatoren
instanceof
if (element instanceof HTMLElement){
doIt();
}
spread-Operator
let list1: number[] = [1, 2, 3];
let list2: number[] = [...list, 4, 5, ..list];
myFunc(1, 2, 3);
myFunc(...list1);