我有这个模块,它将外部库与额外的逻辑组件化,而不直接将<script>标记添加到index.html中:

import 'http://external.com/path/file.js'
//import '../js/file.js'

@Component({
    selector: 'my-app',
    template: `
        <script src="http://iknow.com/this/does/not/work/either/file.js"></script>
        <div>Template</div>`
})
export class MyAppComponent {...}

我注意到ES6规范的导入是静态的,并且是在TypeScript编译期间解析的,而不是在运行时。

总之,让它变得可配置,这样file。js就会从CDN或本地文件夹加载? 如何告诉Angular 2动态加载脚本?


当前回答

import { Injectable } from '@angular/core';
import * as $ from 'jquery';

interface Script {
    src: string;
    loaded: boolean;
}

@Injectable()
export class ScriptLoaderService {
    public _scripts: Script[] = [];

    /**
     * @deprecated
     * @param tag
     * @param {string} scripts
     * @returns {Promise<any[]>}
     */
    load(tag, ...scripts: string[]) {
        scripts.forEach((src: string) => {
            if (!this._scripts[src]) {
                this._scripts[src] = { src: src, loaded: false };
            }
        });

        const promises: any[] = [];
        scripts.forEach(src => promises.push(this.loadScript(tag, src)));

        return Promise.all(promises);
    }

    /**
     * Lazy load list of scripts
     * @param tag
     * @param scripts
     * @param loadOnce
     * @returns {Promise<any[]>}
     */
    loadScripts(tag, scripts, loadOnce?: boolean) {
        debugger;
        loadOnce = loadOnce || false;

        scripts.forEach((script: string) => {
            if (!this._scripts[script]) {
                this._scripts[script] = { src: script, loaded: false };
            }
        });

        const promises: any[] = [];
        scripts.forEach(script => promises.push(this.loadScript(tag, script, loadOnce)));

        return Promise.all(promises);
    }

    /**
     * Lazy load a single script
     * @param tag
     * @param {string} src
     * @param loadOnce
     * @returns {Promise<any>}
     */
    loadScript(tag, src: string, loadOnce?: boolean) {
        debugger;
        loadOnce = loadOnce || false;

        if (!this._scripts[src]) {
            this._scripts[src] = { src: src, loaded: false };
        }

        return new Promise((resolve, _reject) => {
            // resolve if already loaded
            if (this._scripts[src].loaded && loadOnce) {
                resolve({ src: src, loaded: true });
            } else {
                // load script tag
                const scriptTag = $('<script/>')
                    .attr('type', 'text/javascript')
                    .attr('src', this._scripts[src].src);

                $(tag).append(scriptTag);

                this._scripts[src] = { src: src, loaded: true };
                resolve({ src: src, loaded: true });
            }
        });
    }

    reloadOnSessionChange() {
        window.addEventListener('storage', function(data) {
            if (data['key'] === 'token' && data['oldValue'] == null && data['newValue']) {
                document.location.reload();
            }
        });
    }
}

其他回答

@ rahull -kumar的解决方案对我来说很好,但我想在我的typescript中调用我的javascript函数

foo.myFunctions() // works in browser console, but foo can't be used in typescript file

我通过在我的typescript中声明它来修复它:

import { Component } from '@angular/core';
import { ScriptService } from './script.service';
declare var foo;

现在,我可以在typcript文件的任何地方调用foo

在我的例子中,我使用上述技术加载了js和css visjs文件-这非常有效。我从ngOnInit()中调用新函数

注意:我不能通过简单地添加一个<script>和<link>标签到html模板文件来加载它。

loadVisJsScript() { console.log('Loading visjs js/css files...'); let script = document.createElement('script'); script.src = "../../assets/vis/vis.min.js"; script.type = 'text/javascript'; script.async = true; script.charset = 'utf-8'; document.getElementsByTagName('head')[0].appendChild(script); let link = document.createElement("link"); link.type = "stylesheet"; link.href = "../../assets/vis/vis.min.css"; document.getElementsByTagName('head')[0].appendChild(link); }

对于下面的链接,我也有同样的问题。我用一种很简单的方法解决了它。

https://www.gstatic.com/charts/loader.js

我需要访问下面代码中的谷歌变量。但当我把它放到angular类中时,它就不起作用了。

google.charts.load("current", {packages:['corechart']});
google.charts.setOnLoadCallback(drawChart);
function drawChart() {
    var data = google.visualization.arrayToDataTable([
        ["Element", "Density", { role: "style" } ],
        ["Copper", 8.94, "dodgerblue"],
        ["Silver", 10.49, "dodgerblue"],
        ["Gold", 19.30, "dodgerblue"],
        ["Platinum", 21.45, "color: dodgerblue"]
    ]);
var view = new google.visualization.DataView(data);
view.setColumns([0, 1,
    { calc: "stringify",
        sourceColumn: 1,
        type: "string",
        role: "annotation" },
    2]);

var options = {
    title: "Density of Precious Metals, in g/cm^3",
    width: 600,
    height: 400,
    bar: {groupWidth: "50%"},
    legend: { position: "none" },
};
var chart = new google.visualization.ColumnChart(document.getElementById("columnchart_values"));
chart.draw(view, options);

}

我在ts类的顶部创建了一个具有相同名称的全局变量(谷歌),然后该变量自动引用所需的变量。(因为它是全局作用域)那么问题就解决了。

declare var google: any;

我希望能够:

Add a script when the app is being bootstrapped Not do it from a component, because it doesn't feel like it's any component's responsibility Not do it from a directive, because of the same reason as the component Not do it from a service, because unless there's some kind of heavy logic related to an existing service, this doesn't belong IMO to a service Avoid doing it in a module. A module could be fine but it's not as flexible as just using DI and since Angular 15 standalone components are stable so why bother with a module

也就是说,为了在应用程序引导之前做到这一点,这有点棘手。因为我们在那个阶段没有可用的渲染器,并且我们不能访问包含nativeElement的elementRef。

下面是我的看法:

export const YOUR_EXT_LIB_URL_TOKEN = new InjectionToken<string>('YOUR_EXT_LIB_URL_TOKEN');

export const YOUR_SETUP: Provider = {
  provide: APP_INITIALIZER,
  multi: true,
  useFactory: (
    doc: InjectionTokenType<typeof DOCUMENT>,
    rendererFactory: RendererFactory2,
    yourExternalLibToken: string,
  ) => {
    const renderer = rendererFactory.createRenderer(null, null);

    const script = renderer.createElement('script');
    script.type = 'text/javascript';
    script.src = yourExternalLibToken;
    renderer.appendChild(doc.body, script);

    return () => true;
  },
  deps: [DOCUMENT, RendererFactory2, YOUR_EXT_LIB_URL_TOKEN],
};

然后,您所要做的就是提供YOUR_EXT_LIB_URL_TOKEN并传递YOUR_SETUP提供程序。

这样,所有东西都是通过DI注入的,非常灵活。例如,您可以在共享库中提供YOUR_SETUP令牌,并在使用共享库的不同应用程序中提供YOUR_EXT_LIB_URL_TOKEN。

您可以像这样在组件中动态加载多个脚本。ts文件:

 loadScripts() {
    const dynamicScripts = [
     'https://platform.twitter.com/widgets.js',
     '../../../assets/js/dummyjs.min.js'
    ];
    for (let i = 0; i < dynamicScripts.length; i++) {
      const node = document.createElement('script');
      node.src = dynamicScripts[i];
      node.type = 'text/javascript';
      node.async = false;
      node.charset = 'utf-8';
      document.getElementsByTagName('head')[0].appendChild(node);
    }
  }

并在构造函数中调用这个方法,

constructor() {
    this.loadScripts();
}

注意:如果需要动态加载更多脚本,请将它们添加到dynamicScripts数组中。