如何在TypeScript中實例化，初始化和填充數組？

Question

我在打字稿以下類：

class bar { 
    length: number; 
} 

class foo { 
    bars: bar[] = new Array(); 
} 

然後我有：

var ham = new foo(); 
ham.bars = [ 
    new bar() {   // <-- compiler says Expected "]" and Expected ";" 
     length = 1 
    } 
]; 

有沒有辦法做到這一點的打字稿？

UPDATE

我想出了另一種解決方案由具有一套方法返回本身：

class bar { 
    length: number; 

    private ht: number; 
    height(h: number): bar { 
     this.ht = h; return this; 
    } 

    constructor(len: number) { 
     this.length = len; 
    } 
} 

class foo { 
    bars: bar[] = new Array(); 
    setBars(items: bar[]) { 
     this.bars = items; 
     return this; 
    } 
} 

所以你可以如下初始化：

var ham = new foo(); 
ham.setBars(
    [ 
     new bar(1).height(2), 
     new bar(3) 
    ]); 

Answer 1

有ISN像JavaScript或TypeScript中的對象那樣的字段初始化語法。

選項1：

class bar { 
    // Makes a public field called 'length' 
    constructor(public length: number) { } 
} 

bars = [ new bar(1) ]; 

選項2：

interface bar { 
    length: number; 
} 

bars = [ {length: 1} ]; 

Answer 2

如果你真的想有一個名爲參數，再加上有你的對象是你的類的實例，你可以做到以下幾點：

class bar { 
    constructor (options?: {length: number; height: number;}) { 
     if (options) { 
      this.length = options.length; 
      this.height = options.height; 
     } 
    } 
    length: number; 
    height: number; 
} 

class foo { 
    bars: bar[] = new Array(); 
} 

var ham = new foo(); 
ham.bars = [ 
    new bar({length: 4, height: 2}), 
    new bar({length: 1, height: 3}) 
]; 

另外here是打字稿問題追蹤器上的相關項目。