arrays - 在 TypeScript 中，我如何访问数组的成员？

Question

如果我有类似的东西:

var treeArray: TreesArray;
treeArray = [new tree("Maple"),
    new tree("Pine"),
    new tree("Spruce")];`

我如何提醒第二位成员？

这不起作用:alert(treeArray[1]);

更新:抱歉，我应该从一开始就包含完整的代码。正如我所写的那样，警报仍然不起作用。

interface ITrees{
    treeName: string;
}

interface TreesArray{
    [index: number]: ITrees;
    length: number;
}

class tree implements ITrees{
    treeName: string;
    constructor (treeName: string){
        this.treeName = treeName; 
    }
}

var treeArray: TreesArray;
treeArray = [new tree("Maple"),
            new tree("Pine"), 
            new tree("Spruce")];

alert(treeArray([1]);//does not alert "Pine"

Answer 1

它确实有效:

class tree{
    constructor(public treename){       
    }
    toString(){return this.treename}
}
var treeArray: tree[];
treeArray = [new tree("Maple"),
        new tree("Pine"),
        new tree("Spruce")];

alert(treeArray[1]);

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