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?
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();
}
});
}
}
嗨,你可以使用Renderer2和elementRef只需几行代码:
constructor(private readonly elementRef: ElementRef,
private renderer: Renderer2) {
}
ngOnInit() {
const script = this.renderer.createElement('script');
script.src = 'http://iknow.com/this/does/not/work/either/file.js';
script.onload = () => {
console.log('script loaded');
initFile();
};
this.renderer.appendChild(this.elementRef.nativeElement, script);
}
onload函数可以用来在脚本加载后调用脚本函数,如果你必须在ngOnInit()中进行调用,这是非常有用的。
@ 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
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。