systemjs.config.js 角度 2

systemjs.config.js in angular2

我是 angular2 的新手,我想知道 systemjs.config.js 文件中存在的所有对象的用途。

System.config({
    paths: {
        // paths serve as alias
        'npm:': 'node_modules/'
    },
    // map tells the System loader where to look for things
    map: {
        // our app is within the app folder
        app: 'dist',
        main: 'main.js',

        // angular bundles
        '@angular/core': 'npm:@angular/core/bundles/core.umd.js',
        '@angular/common': 'npm:@angular/common/bundles/common.umd.js',
        '@angular/compiler': 'npm:@angular/compiler/bundles/compiler.umd.js',
        '@angular/platform-browser': 'npm:@angular/platform-browser/bundles/platform-browser.umd.js',
        '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic.umd.js',
        '@angular/http': 'npm:@angular/http/bundles/http.umd.js',
        '@angular/router': 'npm:@angular/router/bundles/router.umd.js',
        '@angular/forms': 'npm:@angular/forms/bundles/forms.umd.js',

        // other libraries
        'rxjs': 'npm:rxjs',
        'angular-in-memory-web-api': 'npm:angular-in-memory-web-api/bundles/in-memory-web-api.umd.js',
        'primeng':                   'npm:primeng'      
    },
    // packages tells the System loader how to load when no filename and/or no extension
    packages: {
        app: { main: 'main.js', defaultExtension: 'js' },
        api: { defaultExtension: 'js' },
        rxjs: {defaultExtension: 'js'},
        'node_modules/primeng': {
            format: 'cjs',
            defaultExtension: 'js'
          }
         }

});

例如,上面粘贴的代码有像 paths 这样的对象,可以用来指定别名,以同样的方式我想知道 map 的用法 和地图的所有内部对象,依此类推。

嗯,首先你要知道 npm 包的位置,通常在根目录,因此:

paths: {
    // paths serve as alias
    'npm:': 'node_modules/'
}

然后你给你将要使用的包别名(快捷方式名称),在这种情况下 angular 和一些第 3 方库,如 rxjs,...

map: {
        // our app is within the app folder
        app: 'dist',
        main: 'main.js',

        // angular bundles
        '@angular/core': 'npm:@angular/core/bundles/core.umd.js',
        '@angular/common': 'npm:@angular/common/bundles/common.umd.js',
        '@angular/compiler': 'npm:@angular/compiler/bundles/compiler.umd.js',
        '@angular/platform-browser': 'npm:@angular/platform-browser/bundles/platform-browser.umd.js',
        '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic.umd.js',
        '@angular/http': 'npm:@angular/http/bundles/http.umd.js',
        '@angular/router': 'npm:@angular/router/bundles/router.umd.js',
        '@angular/forms': 'npm:@angular/forms/bundles/forms.umd.js',

        // other libraries
        'rxjs': 'npm:rxjs',
        'angular-in-memory-web-api': 'npm:angular-in-memory-web-api/bundles/in-memory-web-api.umd.js',
        'primeng':                   'npm:primeng'      
    }

因此,在导入库时无需键入整个路径(例如 'npm:@angular/core/bundles/core.umd.js'),您只需导入您为其指定的别名 ('@angular/core')。导入别名时,您确定导入了正确的库。

库全路径前的'npm:',指的是你上面启动的路径'npm'。