在angular 2延迟加载模块中使用外部javascript库,而不是index.html

Question

所以我想在我的Angular 2应用程序中包含一个外部JS库,一个旋转木马滑块.我已经看过很多教程,展示了如何添加它我已经成功完成了,但引用了index.html上的库.

如您所知,每次访问应用程序时都会加载库,无论他们是否访问需要轮播的组件.由于它非常大,我只想在需要的地方加载它,这是在一个延迟加载的模块中.

我没有尝试过,但我确信我可以在使用它的组件中查看脚本标记,但这对我来说感觉不对.

必须有正确的方法.它是什么!？

谢谢!

Answer 1

我们在我们的一个项目中这样做是为了动态加载js库

ScriptStore.ts将包含本地或远程服务器上的脚本路径以及将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,script.service.ts按原样复制

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

declare var document: any;

@Injectable()
export class Script {

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);
        }
    });
}

}

ScriptService在您需要的地方注入它并加载像这样的js库

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