Question

我们正在制作一个不希望看到生产至少一年的网络应用程序，所以我们尽量做到前瞻性思维。

我们正在使用此ES6 polyfill来访问Map或Array.prototype.find等内容。问题是让我们的Typescript代码一起发挥。

例如，TS 1.4中的lib.d.ts不了解Array.prototype.find。我抓住了Typescript源代码，bin文件夹中有一堆d.ts。 lib.core.es6.d.ts和lib.es6.d.ts都有find。我尝试在我们的构建中使用它们，并在它们上使用typescript编译器barfs（“接口中不允许使用计算属性名称”）。

在Typescript中获得ES6类型支持的最佳方法是什么？

Answer 1

诀窍是仅复制你需要的东西。在您的情况下只是find方法。

interface Array<T> {
        /** 
      * Returns the value of the first element in the array where predicate is true, and undefined 
      * otherwise.
      * @param predicate find calls predicate once for each element of the array, in ascending 
      * order, until it finds one where predicate returns true. If such an element is found, find 
      * immediately returns that element value. Otherwise, find returns undefined.
      * @param thisArg If provided, it will be used as the this value for each invocation of 
      * predicate. If it is not provided, undefined is used instead.
      */
    find(predicate: (value: T, index: number, obj: Array<T>) => boolean, thisArg?: any): T;

    /** 
      * Returns the index of the first element in the array where predicate is true, and undefined 
      * otherwise.
      * @param predicate find calls predicate once for each element of the array, in ascending 
      * order, until it finds one where predicate returns true. If such an element is found, find 
      * immediately returns that element value. Otherwise, find returns undefined.
      * @param thisArg If provided, it will be used as the this value for each invocation of 
      * predicate. If it is not provided, undefined is used instead.
      */
    findIndex(predicate: (value: T) => boolean, thisArg?: any): number;
}

var foo = [];
var bar = foo.find((x)=>true);

lib.d.ts Array.prototype.find

1 个答案: