TypeScript允许你声明重载，但是你只能有一个实现，而且这个实现必须有一个与所有重载兼容的签名。在你的例子中，这可以很容易地用一个可选参数来完成，

interface IBox {    
    x : number;
    y : number;
    height : number;
    width : number;
}
    
class Box {
    public x: number;
    public y: number;
    public height: number;
    public width: number;

    constructor(obj?: IBox) {    
        this.x = obj?.x ?? 0
        this.y = obj?.y ?? 0
        this.height = obj?.height ?? 0
        this.width = obj?.width ?? 0;
    }   
}

或者使用更通用的构造函数进行两次重载，

interface IBox {    
    x : number;
    y : number;
    height : number;
        width : number;
}
    
class Box {
    public x: number;
    public y: number;
    public height: number;
    public width: number;

    constructor();
    constructor(obj: IBox); 
    constructor(obj?: IBox) {    
        this.x = obj?.x ?? 0
        this.y = obj?.y ?? 0
        this.height = obj?.height ?? 0
        this.width = obj?.width ?? 0;
    }   
}

参见游乐场

你应该记住……

contructor()

constructor(a:any, b:any, c:any)

它和new()或者new("a"，"b"，"c")一样

Thus

constructor(a?:any, b?:any, c?:any)

和上面一样，而且更灵活…

新()或新的(“a”)或(“a”、“b”)或新(“a”、“b”、“c”)

Box类试图定义多个构造函数实现。

只有最后一个构造函数重载签名被用作类构造函数实现。

在下面的示例中，请注意构造函数实现的定义与前面的任何重载签名都不冲突。

interface IBox = {
    x: number;
    y: number;
    width: number;
    height: number;
}

class Box {
    public x: number;
    public y: number;
    public width: number;
    public height: number;

    constructor() /* Overload Signature */
    constructor(obj: IBox) /* Overload Signature */
    constructor(obj?: IBox) /* Implementation Constructor */ {
        if (obj) {
            this.x = obj.x;
            this.y = obj.y;
            this.width = obj.width;
            this.height = obj.height;
        } else {
            this.x = 0;
            this.y = 0;
            this.width = 0;
            this.height = 0
        }
    }

    get frame(): string {
        console.log(this.x, this.y, this.width, this.height);
    }
}

new Box().frame; // 0 0 0 0
new Box({ x:10, y:10, width: 70, height: 120 }).frame; // 10 10 70 120



// You could also write the Box class like so;
class Box {
    public x: number = 0;
    public y: number = 0;
    public width: number = 0;
    public height: number = 0;

    constructor() /* Overload Signature */
    constructor(obj: IBox) /* Overload Signature */
    constructor(obj?: IBox) /* Implementation Constructor */ {
        if (obj) {
            this.x = obj.x;
            this.y = obj.y;
            this.width = obj.width;
            this.height = obj.height;
        }
    }

    get frame(): string { ... }
}

正如chuckj所说，简单的答案是一个可选形参，但是如果我们想用多个形参重载构造函数，或者我们想改变形参顺序，该怎么办呢?

事实证明，构造函数可以像函数一样重载:

class FooBar {
  public foo?: number;
  public bar?: string;

  // Constructor A
  constructor(foo: number, bar?: string);
  // Constructor B
  constructor(bar: string, foo?: number);
  // Constructor C
  constructor(bar: string);
  // Constructor D
  constructor(foo: number);
  // Constructor E
  constructor();

  constructor(...args: any[]) {
    switch (args.length) {
      case 2:
        if (typeof args[0] === "number") {
          this.foo = args[0];
          this.bar = args[1];
        } else {
          this.bar = args[0];
          this.foo = args[1];
        }
        break;
      case 1:
        if (typeof args[0] === "number") {
          this.foo = args[0];
        } else {
          this.bar = args[0];
        }
    }

    console.log(this.foo, this.bar);
  }
}

const fooBarConstructorA = new FooBar("150", 25);
const fooBarConstructorB = new FooBar(25, "150");
const fooBarConstructorC = new FooBar("150");
const fooBarConstructorD = new FooBar("150");
const fooBarConstructorE = new FooBar();

interface IBox {
    x: number;
    y: number;
    height: number;
    width: number;
}

class Box {
    public x: number;
    public y: number;
    public height: number;
    public width: number;

    constructor(obj: IBox) {
        const { x, y, height, width } = { x: 0, y: 0, height: 0, width: 0, ...obj }
        this.x = x;
        this.y = y;
        this.height = height;
        this.width = width;
    }
}

我知道这是一个老问题，但1.4中的新功能是联合类型;对所有函数重载(包括构造函数)使用这些。例子:

class foo {
    private _name: any;
    constructor(name: string | number) {
        this._name = name;
    }
}
var f1 = new foo("bar");
var f2 = new foo(1);