示例可以是

script-loader.service。ts文件

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

declare let document: any;

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};
  }
});

let 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) {
loadOnce = loadOnce || false;

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

let 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) {
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
    let 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});
  }
 });
 }
 }

和使用

第一次注射

  constructor(
  private _script: ScriptLoaderService) {
  }

然后

ngAfterViewInit()  {
this._script.loadScripts('app-wizard-wizard-3',
['assets/demo/default/custom/crud/wizard/wizard.js']);

}

or

    this._script.loadScripts('body', [
  'assets/vendors/base/vendors.bundle.js',
  'assets/demo/default/base/scripts.bundle.js'], true).then(() => {
  Helpers.setLoading(false);
  this.handleFormSwitch();
  this.handleSignInFormSubmit();
  this.handleSignUpFormSubmit();
  this.handleForgetPasswordFormSubmit();
});

我有一个很好的方法来动态加载脚本! 现在我在我的项目中使用ng6, echarts4 (>700Kb)，ngx-echarts3。当我通过ngx-echarts的文档使用它们时，我需要在angular中导入echarts。json: “脚本”:["。/ node_modules / echarts / dist / echarts.min.js”) 因此在登录模块中，页面同时加载scripts.js，这是一个大文件!我不想要。

所以，我认为angular将每个模块作为一个文件加载，我可以插入一个路由器解析器来预加载js，然后开始加载模块!

/ / PreloadScriptResolver.service.js

/**动态加载js的服务 */
@Injectable({
  providedIn: 'root'
})
export class PreloadScriptResolver implements Resolve<IPreloadScriptResult[]> {
  // Here import all dynamically js file
  private scripts: any = {
    echarts: { loaded: false, src: "assets/lib/echarts.min.js" }
  };
  constructor() { }
  load(...scripts: string[]) {
    const promises = scripts.map(script => this.loadScript(script));
    return Promise.all(promises);
  }
  loadScript(name: string): Promise<IPreloadScriptResult> {
    return new Promise((resolve, reject) => {
      if (this.scripts[name].loaded) {
        resolve({ script: name, loaded: true, status: 'Already Loaded' });
      } else {
        const script = document.createElement('script');
        script.type = 'text/javascript';
        script.src = this.scripts[name].src;
        script.onload = () => {
          this.scripts[name].loaded = true;
          resolve({ script: name, loaded: true, status: 'Loaded' });
        };
        script.onerror = (error: any) => reject({ script: name, loaded: false, status: 'Loaded Error:' + error.toString() });
        document.head.appendChild(script);
      }
    });
  }

  resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Promise<IPreloadScriptResult[]> {
   return this.load(...route.routeConfig.data.preloadScripts);
  }
}

然后在子模块-routing.module中。导入PreloadScriptResolver:

const routes: Routes = [
  {
    path: "",
    component: DashboardComponent,
    canActivate: [AuthGuardService],
    canActivateChild: [AuthGuardService],
    resolve: {
      preloadScripts: PreloadScriptResolver
    },
    data: {
      preloadScripts: ["echarts"]  // important!
    },
    children: [.....]
}

这段代码工作得很好，它承诺:js文件加载后，然后模块开始加载!这个解析器可以在许多路由器中使用

如果你正在使用system.js，你可以在运行时使用System.import():

export class MyAppComponent {
  constructor(){
    System.import('path/to/your/module').then(refToLoadedModule => {
      refToLoadedModule.someFunction();
    }
  );
}

如果你正在使用webpack，你可以充分利用它强大的代码分割支持。确保:

export class MyAppComponent {
  constructor() {
     require.ensure(['path/to/your/module'], require => {
        let yourModule = require('path/to/your/module');
        yourModule.someFunction();
     }); 
  }
}

Angular有防止用户直接干扰html输出的逻辑。所以你必须让Angular通过在Angular中给出那个方向来注入标签。json文件。

首先，您必须获取脚本文件。有两种方法:

下载脚本文件(例如。somelibrary.js)

把它放在资产文件夹中 把脚本的相对路径，放到angular的“scripts”部分。json文件:

"scripts": [
  "src/assets/somelibrary.js"
]

使用npm/yarn安装脚本:

把脚本的相对路径，放到angular的“scripts”部分。json文件:

"scripts": [
  "./node_modules/somelibrary/dist/somelibrary.min.js"
]

这可能有用。这段代码动态地将<script>标记附加到单击按钮时的html文件头部。

const url = 'http://iknow.com/this/does/not/work/either/file.js';

export class MyAppComponent {
    loadAPI: Promise<any>;

    public buttonClicked() {
        this.loadAPI = new Promise((resolve) => {
            console.log('resolving promise...');
            this.loadScript();
        });
    }

    public loadScript() {
        console.log('preparing to load...')
        let node = document.createElement('script');
        node.src = url;
        node.type = 'text/javascript';
        node.async = true;
        node.charset = 'utf-8';
        document.getElementsByTagName('head')[0].appendChild(node);
    }
}

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。