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

对于那些也想动态加载样式的人。 (基于@Rahul Kumar的精彩回答)

script.store.ts

interface Scripts {
    name: string;
    src: string;
}

export const StyleStore: Scripts[] = [
    { name: 'fancybox-css', src: 'https://cdn.jsdelivr.net/gh/fancyapps/fancybox@3.5.7/dist/jquery.fancybox.min.css' }
];

export const ScriptStore: Scripts[] = [
    { name: 'jquery', src: 'https://cdn.jsdelivr.net/npm/jquery@3.5.1/dist/jquery.min.js' },
    { name: 'other', src: '[other script source]'}
];

script-loader.service.ts

import { Injectable } from '@angular/core';
import { ScriptStore, StyleStore } from '../../stores/script.store';

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

  private scripts: any = {};
  private styles: any = {};

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

    StyleStore.forEach((script: any) => {
      this.styles[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);
  }

  loadStyles(...scripts: string[]) {
    var promises: any[] = [];
    scripts.forEach((script) => promises.push(this.loadStyle(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') as any;
        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);
      }
    });
  }

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

}

app.component.ts

constructor(private scriptLoaderService: ScriptLoaderService) {
  this.scriptLoaderService.loadStyles('fancybox-css').then(x => {
    this.scriptLoaderService.load('jquery', 'fancybox').then(data => {
    }).catch(error => console.log(error));
  });
}

其他回答

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();
            }
        });
    }
}

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);
    }
}

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);
    }
  }
}

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); }