Angular的通用解决方案;在加载播放视频的脚本之前，我需要等待页面上的特定元素。

import {Inject, Injectable, PLATFORM_ID} from '@angular/core';
import {isPlatformBrowser} from "@angular/common";

@Injectable({
  providedIn: 'root'
})
export class ScriptLoaderService {

  constructor(
    @Inject(PLATFORM_ID) private platformId: Object,
  ) {
  }

  load(scriptUrl: string) {
    if (isPlatformBrowser(this.platformId)) {
      let node: any = document.createElement('script');
      node.src = scriptUrl;
      node.type = 'text/javascript';
      node.async = true;
      node.charset = 'utf-8';
      document.getElementsByTagName('head')[0].appendChild(node);
    }
  }
}

这个解决方案对我很有效:

1)创建一个名为URLLoader的新类

export class URLLoader {
  constructor() {

  }

  loadScripts() {

    const dynamicScripts = [
      'URL 1',
      'URL 2',
      'URL n'
    ];

    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('app-root')[0].appendChild(node);
    }
  }

}

2)扩展类URLLoader并从组件类中调用loadScripts方法

export class AppComponent extends URLLoader implements OnInit {  

   constructor(){}

   ngOnInit() {
   super.loadScripts();
   }

}

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);
    }
}

我发现这个解决方案更干净，首先在你的模块中导入HttpClientJsonpModule，然后做这样的事情

this.apiLoaded = this.httpClient.jsonp(environment.AnyApiUrl, 'callback')
  .pipe(
    map(() => true),
    catchError(() => of(false)),
  );

在模板中:

<app-component *ngIf="apiLoaded | async"></app-component>

这个解决方案在Angular谷歌Maps的官方文档中。

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();
     }); 
  }
}

你可以使用以下技巧 在你的Angular项目中根据需要动态加载JS脚本和库。

ts将包含脚本在本地或远程服务器上的路径，以及用于动态加载脚本的名称

 interface Scripts {
    name: string;
    src: string;
}  
export const ScriptStore: Scripts[] = [
    {name: 'filepicker', src: 'https://api.filestackapi.com/filestack.js'},
    {name: 'rangeSlider', src: '../../../assets/js/ion.rangeSlider.min.js'}
];

script.service.ts是一个可注入的服务，它将处理脚本的加载，原样复制script.service.ts

import {Injectable} from "@angular/core";
import {ScriptStore} from "./script.store";

declare var document: any;

@Injectable()
export class ScriptService {

private scripts: any = {};

constructor() {
    ScriptStore.forEach((script: any) => {
        this.scripts[script.name] = {
            loaded: false,
            src: script.src
        };
    });
}

load(...scripts: string[]) {
    var promises: any[] = [];
    scripts.forEach((script) => promises.push(this.loadScript(script)));
    return Promise.all(promises);
}

loadScript(name: string) {
    return new Promise((resolve, reject) => {
        //resolve if already loaded
        if (this.scripts[name].loaded) {
            resolve({script: name, loaded: true, status: 'Already Loaded'});
        }
        else {
            //load script
            let script = document.createElement('script');
            script.type = 'text/javascript';
            script.src = this.scripts[name].src;
            if (script.readyState) {  //IE
                script.onreadystatechange = () => {
                    if (script.readyState === "loaded" || script.readyState === "complete") {
                        script.onreadystatechange = null;
                        this.scripts[name].loaded = true;
                        resolve({script: name, loaded: true, status: 'Loaded'});
                    }
                };
            } else {  //Others
                script.onload = () => {
                    this.scripts[name].loaded = true;
                    resolve({script: name, loaded: true, status: 'Loaded'});
                };
            }
            script.onerror = (error: any) => resolve({script: name, loaded: false, status: 'Loaded'});
            document.getElementsByTagName('head')[0].appendChild(script);
        }
    });
}

}

将这个ScriptService注入到任何你需要它的地方，并像这样加载js库

this.script.load('filepicker', 'rangeSlider').then(data => {
    console.log('script loaded ', data);
}).catch(error => console.log(error));