[typeScript语法4]class

桃扇骨 2022-06-14 04:28 207阅读 0赞

/**练习typeScript-4 class
     * Created by liyanq on 17/6/9.
     */
    
    /*注意点
     * 1,abstract函数只能出现在abstract类中
     * 2,abstract函数的参数不能带默认值
     * 3,private readonly注意顺序
     * 4,*/
    
    class Animal {
        name: string;
    
        constructor(theName: string) {
            this.name = theName;
        }
    
        move(distanceInMeters: number = 0) {
            console.log(`${this.name} moved ${distanceInMeters}m.`);
        }
    }
    
    class Snake extends Animal {
        constructor(name: string) {
            super(name);
        }
    
        move(distanceInMeters = 5) {
            console.log("Slithering...");
            super.move(distanceInMeters);
        }
    }
    
    class Horse extends Animal {
        constructor(name: string) {
            super(name);
        }
    
        move(distanceInMeters = 45) {
            console.log("Galloping...");
            super.move(distanceInMeters);
        }
    }
    
    let sam = new Snake("Sammy the Python");
    let tom: Animal = new Horse("Tommy the Palomino");
    
    sam.move();
    tom.move(34);
    
    class Octopus {
    
        private numberOfLegs: number = 8;
    
        constructor(public name: string) {
            console.log(this.numberOfLegs);
        }
    }
    let dad = new Octopus("Man with the 8 strong legs");
    // dad.name = "Man with the 3-piece suit";
    //----------Accessors-----------//
    let passcode = "secret passcode";
    class Employee {
        private _fullName: string;
        get fullName(): string {
            console.log("get getfullName(): string");
            return this._fullName;
        }
    
        set fullName(newName: string) {
            if (passcode && passcode == "secret passcode") {
                this._fullName = newName;
            }
            else {
                console.log("Error: Unauthorized update of employee!");
            }
        }
    }
    let employee = new Employee();
    employee.fullName = "Bob Smith";
    if (employee.fullName) {
    }
    //---------------Static Properties---------------
    class Grid {
        static origin = {x: 0, y: 0};
    
        calculateDistanceFromOrigin(point: {x: number, y: number;}) {
            let xDist = (point.x - Grid.origin.x);
            let yDist = (point.y - Grid.origin.y);
            return (xDist * xDist + yDist * yDist) * this.scale;
        }
    
        constructor(public scale: number) {
        }
    }
    
    let grid1 = new Grid(1.0);  // 1x scale
    let grid2 = new Grid(5.0);  // 5x scale
    
    console.log(grid1.calculateDistanceFromOrigin({x: 10, y: 10}));
    console.log(grid2.calculateDistanceFromOrigin({x: 10, y: 10}));
    
    
    class Greeter {
        static standardGreeting = "Hello, there";
        greeting: string;
        greet() {
            if (this.greeting) {
                return "Hello, " + this.greeting;
            }
            else {
                return Greeter.standardGreeting;
            }
        }
    }
    
    /*typeof Greeter:give me the type of the Greeter class itself*/
    let greeterMaker: typeof Greeter = Greeter;
    console.log(typeof Greeter);//function
    greeterMaker.standardGreeting = "Hey there!";
    console.log(greeterMaker);//{ [Function: Greeter] standardGreeting: 'Hey there!' }
    let greeter2: Greeter = new greeterMaker();
    console.log(greeter2.greet());
    
    let  g:Greeter = new Greeter();
    console.log(g.greet());//注意:这里也改了啊,也是Hey there!
    
    //-----------Using a class as an interface-----//
    //看了一眼，接口继承类，不学也罢，省的乱～～～