TypeScript class interface

Posted by On 6月 21, 2016 0 Comment

TypeScript class

JavaScript doesn’t have class idea.
TypeScript has.
Finally, TypeScript compiles Javascript. It becomes prototype.

Example

class Helo {
    message: string;

    constructor(message: string) {
        this.message = message;
    }

    sayHello() {
        return "Hello, " + this.message;
    }
}

Use this

let greeter = new Helo("Erichi");

console.log(greeter.message);    // Can access

console.log(greeter.sayHello());

private, protected, public

We can use access attr like other language

class Employee {
    private name: string;  // private, protected, private
    constructor(theName: string){
        this.name = theName;
    }
}

Other Sample

class Animal {
    name: string;
    constructor(theName: string) {
        this.name = theName;
    }

    run(kilo: number = 1) {
        console.log(`${this.name} run ${kilo}`)
    }
}

var anim = new Animal("lion");
anim.run();

class Bear extends Animal {
    constructor(name: string) {
        super(name);
    }
    run(kilo: number = 5) {  //public, private
        super.run(kilo);
    }
}

Interface

TypeScript has interface like Java, C#

interface ClockInterface {
    currentTime: Date;      // no let
    setTime(d: Date);
}

class Clock implements ClockInterface {
    currentTime: Date;

    //let num: number;   Error

    constructor(h: number, m: number){}
    setTime(d: Date) {
        this.currentTime = d;
    }
}

interface Counter {
    (start: number): string;
    interval: number;
    reset(): void;
}

function getCounter(): Counter {
    let counter = <Counter>function (start: number) { };
    counter.interval = 123;
    counter.reset = function () { };
    return counter;
}

Implements more than 2 interfaces

interface M1 {
    lost();
}

interface M2 {
    play();
}

class M3 implements M1, M2 {
    lost() {

    }

    play() {

    }
}

Reverse!!

interface can extend class

class Base {
    private state: any;
}

interface Next extends Base {

}

interface Next2 extends Next {

}

Abstract

We can also use abstract

abstract class Player {
    abstract hit(): void;
    play(): void {
        console.log("Ball");
    }
}

class NormalPlayer extends Player {
    hit(): void {
        console.log("I am normal player");
    }
}

static

class Grid {
    static origin = {x:0, y:0};
}

console.log(Grid.origin);

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