我有这个模块，它将外部库与其他逻辑组件化，而无需将<script>标记直接添加到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import是静态的，并且在TypeScript转换过程中而不是在运行时解析。
无论如何要使其可配置，以便从CDN或本地文件夹加载file.js？ 如何告诉Angular 2动态加载脚本？
答案 0 :(得分：93)
您可以使用以下技巧 在Angular项目中按需动态加载JS脚本和库。
script.store.ts 将在本地或远程服务器上包含脚本的路径以及将使用的名称动态加载脚本
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，复制script.service.ts，因为它是
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);
}
});
}
}
在您需要的地方注入此ScriptService并加载像这样的js库
this.script.load('filepicker', 'rangeSlider').then(data => {
console.log('script loaded ', data);
}).catch(error => console.log(error));
答案 1 :(得分：45)
如果您正在使用system.js，则可以在运行时使用System.import()：
export class MyAppComponent {
constructor(){
System.import('path/to/your/module').then(refToLoadedModule => {
refToLoadedModule.someFunction();
}
);
}
如果您正在使用webpack，则可以通过require.ensure充分利用其强大的代码拆分支持：
export class MyAppComponent {
constructor() {
require.ensure(['path/to/your/module'], require => {
let yourModule = require('path/to/your/module');
yourModule.someFunction();
});
}
}
答案 2 :(得分：36)
这可能有用。此代码会在点击按钮时动态地将<script>标记附加到html文件的head。
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);
}
}
答案 3 :(得分：17)
我修改了@rahul kumars的答案，所以它改为使用Observables：
import { Injectable } from "@angular/core";
import { Observable } from "rxjs/Observable";
import { Observer } from "rxjs/Observer";
@Injectable()
export class ScriptLoaderService {
private scripts: ScriptModel[] = [];
public load(script: ScriptModel): Observable<ScriptModel> {
return new Observable<ScriptModel>((observer: Observer<ScriptModel>) => {
var existingScript = this.scripts.find(s => s.name == script.name);
// Complete if already loaded
if (existingScript && existingScript.loaded) {
observer.next(existingScript);
observer.complete();
}
else {
// Add the script
this.scripts = [...this.scripts, script];
// Load the script
let scriptElement = document.createElement("script");
scriptElement.type = "text/javascript";
scriptElement.src = script.src;
scriptElement.onload = () => {
script.loaded = true;
observer.next(script);
observer.complete();
};
scriptElement.onerror = (error: any) => {
observer.error("Couldn't load script " + script.src);
};
document.getElementsByTagName('body')[0].appendChild(scriptElement);
}
});
}
}
export interface ScriptModel {
name: string,
src: string,
loaded: boolean
}
答案 4 :(得分：11)
您可以在component.ts文件中加载动态多个脚本：
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此方法，
constructor() {
this.loadScripts();
}
注意：要动态加载更多脚本，请将它们添加到dynamicScripts数组。
答案 5 :(得分：8)
另一种选择是利用scriptjs package来解决问题
允许您从任何URL按需加载脚本资源
示例
安装软件包：
npm i scriptjs
和type definitions for scriptjs：
npm install --save @types/scriptjs
然后导入$script.get()方法：
import { get } from 'scriptjs';
并最终加载脚本资源，在我们的示例中为Google Maps库：
export class AppComponent implements OnInit {
ngOnInit() {
get("https://maps.googleapis.com/maps/api/js?key=", () => {
//Google Maps library has been loaded...
});
}
}
答案 6 :(得分：6)
您好，只需几行代码即可使用Renderer2和elementRef：
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函数可用于在脚本加载后调用脚本函数，如果必须在ngOnInit（）中进行调用，这将非常有用
答案 7 :(得分：4)
我有一个动态加载脚本的好方法！ 现在我在项目中使用ng6，echarts4（> 700Kb），ngx-echarts3。当我由ngx-echarts的文档使用它们时，我需要在angular.json中导入echarts： “脚本”：[“ ./ node_modules / echarts / dist / echarts.min.js”] 因此，在登录模块的页面中，加载scripts.js时，这是个大文件！我不要。
因此，我认为angular将每个模块作为文件加载，我可以插入路由器解析器以预加载js，然后开始模块加载！
// PreloadScriptResolver.service.js
String然后在submodule-routing.module.ts中，导入此PreloadScriptResolver：
/**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);
}
}
此代码运行良好，并且承诺：加载js文件后，模块才开始加载！该解析器可以在许多路由器中使用
答案 8 :(得分：2)
import { Component } from '@angular/core';
import { ScriptService } from './script.service';
declare var foo;
我通过在我的打字稿中声明它来修复它：
wxWindow::SetDoubleBuffered()现在，我可以在我的类型文件中的任何地方调用 foo
答案 9 :(得分：2)
在我的情况下，我使用上述技术加载了js和css visjs个文件 - 效果很好。我从ngOnInit()
注意： 我可以不只需添加<script>和<link>标记即可加载html模板文件。
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);
}
答案 10 :(得分：1)
我使用新的渲染器api
完成了此代码段 constructor(private renderer: Renderer2){}
addJsToElement(src: string): HTMLScriptElement {
const script = document.createElement('script');
script.type = 'text/javascript';
script.src = src;
this.renderer.appendChild(document.body, script);
return script;
}
然后像这样称呼它
this.addJsToElement('https://widgets.skyscanner.net/widget-server/js/loader.js').onload = () => {
console.log('SkyScanner Tag loaded');
}
<强> StackBlitz
答案 11 :(得分：0)
我在下面的链接中遇到了同样的问题。我以一种非常简单的方式解决了它。
https://www.gstatic.com/charts/loader.js
我需要在下面的代码中访问 google 变量。但是当我把它放在angular类中时它不起作用。
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同名的全局变量（google），然后该变量自动引用所需的变量。（因为它是全局作用域）然后问题就解决了。
declare var google: any;
答案 12 :(得分：0)
对于那些也想动态加载样式的人。 （基于 @Rahul Kumar 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));
});
}
答案 13 :(得分：0)
角度通用解决方案，请注意，在加载脚本播放视频之前，我需要等待页面上出现特定元素：
从'@ angular / core'导入{Inject，Injectable，PLATFORM_ID}; 从“ @ angular / common”导入{isPlatformBrowser}；
@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);
}
}
}
答案 14 :(得分：0)
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();
}
});
}
}
答案 15 :(得分：0)
一个样本可以是
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});
}
});
}
}
和用法
首次注入
constructor(
private _script: ScriptLoaderService) {
}
然后
ngAfterViewInit() {
this._script.loadScripts('app-wizard-wizard-3',
['assets/demo/default/custom/crud/wizard/wizard.js']);
}
或
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();
});
答案 16 :(得分：0)
@ d123546 我遇到了同样的问题，现在使用像这样的组件中的ngAfterContentInit（Lifecycle Hook）来实现它：
import { Component, OnInit, AfterContentInit } from '@angular/core';
import { Router } from '@angular/router';
import { ScriptService } from '../../script.service';
@Component({
selector: 'app-players-list',
templateUrl: './players-list.component.html',
styleUrls: ['./players-list.component.css'],
providers: [ ScriptService ]
})
export class PlayersListComponent implements OnInit, AfterContentInit {
constructor(private router: Router, private script: ScriptService) {
}
ngOnInit() {
}
ngAfterContentInit() {
this.script.load('filepicker', 'rangeSlider').then(data => {
console.log('script loaded ', data);
}).catch(error => console.log(error));
}
答案 17 :(得分：-1)
您可以使用 Google 跟踪代码管理器来管理您的外部脚本，而无需编写代码。对于非技术用户和技术用户来说，这是一个完美的解决方案。