Question

嗨，我在Typescript中有界面：

interface sprite_loading {
[index: number]: {
    URL: string,
    name: string
}}

我正在类中创建一个数组：

public spriteLoading: sprite_loading;

但是当我尝试使用每个数组时：

private preload() {
    var phaser = this;
    this.spriteLoading.forEach(function (element) { //here is the problem
        phaser.game.load.image(element.name, element.URL);
    });

}

我收到此错误，但代码有效。

engine.ts:57:28 - error TS2339: Property 'forEach' does not exist on type 'sprite_loading'.

为什么会出现此错误？我确定spriteLoading是一个数组。

Answer 1

如果您依赖数组，则可以免费获取它的定义。示例：

interface sprite_loading extends Array<{ URL: string, name: string}> {
    [index: number]: {
        URL: string,
        name: string
    }
}

let example: sprite_loading = [
    { URL: 'foo', name: 'foo' },
    { URL: 'bar', name: 'bar' },
    { URL: 'baz', name: 'baz' }
];

example.forEach((val) => console.log(val.URL));

如果您的sprite_loading界面不是特别时髦，您可能更喜欢定义每个条目的类型，因为它们更简洁：

type Sprite = { URL: string, name: string, things: Thing[] };

let example: sprite_loading = [
    { URL: 'foo', name: 'foo' },
    { URL: 'bar', name: 'bar' },
    { URL: 'baz', name: 'baz' }
];

这是定义其他数组成员的一种巧妙方法：

type Thing = { thingness: number };
type Sprite = { URL: string, name: string, things: Thing[] };

let example: Sprite[] = [
    { URL: 'foo', name: 'foo', things: [{ thingness: 5}, { thingness: 8}] },
    { URL: 'bar', name: 'bar', things: [] },
    { URL: 'baz', name: 'baz', things: [] }
];

example.forEach((val) => console.log(val.URL));

Typescript编译器错误：sprite_loading类型中不存在forEach属性

1 个答案: