Javascript 如何在 TypeScript 中实例化、初始化和填充数组？
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How to instantiate, initialize and populate an array in TypeScript?
提问by Ray Cheng
I have the following classes in TypeScript:
我在 TypeScript 中有以下类：
class bar {
length: number;
}
class foo {
bars: bar[] = new Array();
}
And then I have:
然后我有：
var ham = new foo();
ham.bars = [
new bar() { // <-- compiler says Expected "]" and Expected ";"
length = 1
}
];
Is there a way to do that in TypeScript?
有没有办法在 TypeScript 中做到这一点？
UPDATE
更新
I came up with another solution by having a set method to return itself:
我想出了另一种解决方案，通过 set 方法返回自身：
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;
}
}
so you can initialize it as below:
所以你可以初始化它如下：
var ham = new foo();
ham.setBars(
[
new bar(1).height(2),
new bar(3)
]);
采纳答案by Ryan Cavanaugh
There isn't a field initialization syntax like that for objects in JavaScript or TypeScript.
没有像 JavaScript 或 TypeScript 中的对象那样的字段初始化语法。
Option 1:
选项1：
class bar {
// Makes a public field called 'length'
constructor(public length: number) { }
}
bars = [ new bar(1) ];
Option 2:
选项 2：
interface bar {
length: number;
}
bars = [ {length: 1} ];
回答by orad
If you really want to have named parameters plus have your objects be instances of your class, you can do the following:
如果您真的想要命名参数并且让您的对象成为您的类的实例，您可以执行以下操作：
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})
];
Also here's the related item on typescript issue tracker.
另外这里是打字稿问题跟踪器的相关项目。
回答by Adel Bachene
A simple solution could be:
一个简单的解决方案可能是：
interface bar {
length: number;
}
let bars: bar[];
bars = [];
回答by ArDumez
An other solution:
另一种解决方案：
interface bar {
length: number;
}
bars = [{
length: 1
} as bar];
回答by Liam Hogan
If you would like to 'add' additional items to a page, you may want to create an array of maps. This is how I created an array of mapsand then added results to it:
如果您想向页面“添加”其他项目，您可能需要创建一个地图数组。这就是我创建地图数组然后向其中添加结果的方式：
import { Product } from '../models/product';
products: Array<Product>; // Initialize the array.
[...]
let i = 0;
this.service.products( i , (result) => {
if ( i == 0 ) {
// Create the first element of the array.
this.products = Array(result);
} else {
// Add to the array of maps.
this.products.push(result);
}
});
Where product.tslook like...
凡product.ts样子...
export class Product {
id: number;
[...]
}
