任何方式指定类型自我？或解决方法“属性类型不兼容”。

Question

我有两个类，Line和Wall。线类是父类，并具有只接受线阵列的函数，并且只返回它过滤的结果。
墙上的课程也是如此，但对于墙壁来说。

class Line { 
    public start: Point 
    public end: Point 

    constructor(start: Point, end: Point) { 
     this.start = start 
     this.end = end 
    } 

    collide(lines: Line[]):Line[] { 
     return lines.filter((line) => {return true || false}) 
    } 
} 

和墙壁类：

class Wall extends Line { 
    public start: Point 
    public end: Point 
    public thickness: number 

    private collideWith: Wall[] 

    constructor(start: Point, end: Point,thickness: number) { 
     super(start,end) 
     this.thickness = thickness 
    } 

    collide(walls: Wall[]):Wall[] { 
     return this.collideWith = walls.filter((wall) => {return true || false}) 
     // I would love if this could return just void 
     // since it update private property only, 
     // but returning Wall[] works too 
    } 
} 

此代码产生一个错误：

file.ts(line,7): error TS2415: Class 'Wall' incorrectly extends base class 'Line'. 
Types of property 'collide' are incompatible. 
    Type '(walls: Wall[]) => void' is not assignable to type '(lines: Line[]) => Line[]'. 
     Types of parameters 'walls' and 'lines' are incompatible. 
     Type 'Wall[]' is not assignable to type 'Line[]'. 
      Type 'Wall' is not assignable to type 'Line'. 
      Types of property 'collide' are incompatible. 
       Type '(walls: Wall[]) => void' is not assignable to type '(lines: Line[]) => Line[]'. 
       Types of parameters 'walls' and 'lines' are incompatible. 
        Type 'Wall[]' is not assignable to type 'Line[]'. 
        Type 'Wall' is not assignable to type 'Line'. 

如何应对这种情况？

Answer 1

从代码：

// I would love if this could return just void 
    // since it update private property only, 
    // but returning Wall[] works too 

对于子类返回void父类也必须返回void。这是因为OO多态性。试想一下：

var foo:Line; 
var bar: Wall; 
foo = bar; // polymorphism. After all `Wall` is just `Line` with other stuff 
var x = foo.collide(); // Actually calls `bar.collide`. So signatures must be compatible. 

更新（使用self[]型）：

其在打字稿称为this类型。这里是一个样本：

interface Point {x:number,y:number} 

class Line { 
    public start: Point 
    public end: Point 

    constructor(start: Point, end: Point) { 
     this.start = start 
     this.end = end 
    } 

    collide(lines: this[]) { 
     return lines.filter((line) => {return true || false}); 
    } 
} 

class Wall extends Line { 
    public start: Point 
    public end: Point 
    public thickness: number 

    private collideWith: Wall[] 

    constructor(start: Point, end: Point,thickness: number) { 
     super(start,end) 
     this.thickness = thickness 
    } 

    collide(walls: this[]) { 
     return this.collideWith = walls.filter((wall) => {return true || false}); 
    } 
}