TypeScript 类型化数组使用 [英] TypeScript typed array usage

问题描述

我有一个像这样开头的 TypeScript 类定义；

I have a TypeScript class definition that starts like this;

module Entities {          

    export class Person {
        private _name: string;
        private _possessions: Thing[];
        private _mostPrecious: Thing;

        constructor (name: string) {
            this._name = name;
            this._possessions = new Thing[100];
        }

看起来 Thing 类型的数组没有正确转换为相应的 Javascript 数组类型.这是生成的 JavaScript 的片段:

Looks like an array of type Thing does not get translated correctly to the corresponding Javascript array type. This is a snippet from the generated JavaScript:

function Person(name) {
    this._name = name;
    this._possessions = new Entities.Thing[100]();
}

执行包含Person对象的代码，尝试初始化_possession字段时抛出异常:

Executing code containing a Person object, throw an exception when attempting to initialize the _possession field:

错误是0x800a138f - Microsoft JScript 运行时错误:无法获取属性‘100’的值:对象为空或未定义".

Error is "0x800a138f - Microsoft JScript runtime error: Unable to get value of the property '100': object is null or undefined".

如果我将 _possession 的类型更改为 any[] 并使用 new Array() 初始化 _possession，则不会抛出异常.我错过了什么吗?

If I change the type of _possession to any[] and initialize _possession with new Array() exception is not thrown. Did I miss something?

推荐答案

您的语法有错误:

this._possessions = new Thing[100]();

这不会创建事物数组".要创建一个数组，你可以简单地使用数组字面量表达式:

This doesn't create an "array of things". To create an array of things, you can simply use the array literal expression:

this._possessions = [];

如果要设置长度的数组构造函数:

Of the array constructor if you want to set the length:

this._possessions = new Array(100);

我创建了一个简短的工作示例，您可以在 游乐场.

I have created a brief working example you can try in the playground.

module Entities {  

    class Thing {

    }        

    export class Person {
        private _name: string;
        private _possessions: Thing[];
        private _mostPrecious: Thing;

        constructor (name: string) {
            this._name = name;
            this._possessions = [];
            this._possessions.push(new Thing())
            this._possessions[100] = new Thing();
        }
    }
}

这篇关于TypeScript 类型化数组使用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！