Typescript 使用 Array.find 引发错误

Question

我刚刚完成了 Angular 2.0 Tour of Heroes 教程，并添加了以下 Gulp 文件（为本示例进行了简化）来构建它：

var del = require('del');
var gulp = require('gulp');
var ts = require('gulp-typescript');
var sourcemaps = require('gulp-sourcemaps');
var tsProject = ts.createProject('tsconfig.json');

gulp.task('transpile-ts', function() {
    var tsResult = gulp.src(paths.allTypeScript)
        .pipe(sourcemaps.init())
        .pipe(ts(tsProject));

    return tsResult.js
        .pipe(sourcemaps.write('.'))
        .pipe(gulp.dest(paths.dest_js));
});

我想在dashboard.component.ts中添加一个Array.find方法如下：

ngOnInit() {
    let newVar: Array<number> = new Array();
    newVar.push(0);
    newVar.push(1);
    newVar.find(d => d == 1);

    this._heroService.getHeroes()
        .then(heroes => this.heroes = heroes.slice(1,5));
}

当我运行命令“gulp transpile-ts”时，我收到以下错误：

app\dashboard.component.ts(26,16)：错误 TS2339：属性“查找”不存在 在类型“数字[]”上。

我包含了 es6-shim.d.ts，因此“find”方法确实存在于“interface Array”下。

我还尝试使用 Grunt 运行相同的任务，但发生了相同的问题，所以这不是 Gulp 问题。

关于什么可能导致这种情况的任何想法？

Answer 1

我已经包含了 es6-shim.d.ts，所以“find”方法确实存在于“interface Array”下。

显然 shim 没有将 find 方法添加到 Array。你应该有：

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;
}

更新

即使是多个声明也不应该导致错误。下面的编译就好了：

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;    

}
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;    
}

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

所以检查 es6-shim.d.ts 的内容以确保它确认。

Answer 2

经过调查，我注意到在 CMD 行中使用“tsc”来转换 Typsecript 时，一切都按预期工作。而不是在我的 gulp 文件中使用 'gulp.src' 我应该使用 'tsProject.src' 来模拟它。

这里已回答https://github.com/ivogabe/gulp-typescript/issues/313。