Angular 2 Best approach to use FileSaver.js

问题:

I need to use the FileSaver.js (https://github.com/eligrey/FileSaver.js/) in my Angular2 application.

I know I can add it as a script file in main html page and it will work. But I was wondering what would be the best approach in case of an Angular 2 (TypeScript) application so that I can just call window.saveAs to save file.

回答1:

I managed to get it work using this approach (Angular-CLI):

npm install file-saver --save
npm install @types/file-saver --save

After that import Filesaver in component:

import * as FileSaver from 'file-saver';

And you can use it like this:

    let blob = new Blob([document.getElementById('exportDiv').innerHTML], {
            type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-16le"
        });
    FileSaver.saveAs(blob, "export.xls");    

As you can see, you don't have to add anything in angular-cli.json. Just install library and it's types, import it and you are ready to go.

回答2:

If you're using Angular-CLI to build your project, you can install it by running

npm install file-saver --save

Since there aren't any typings for FileSaver, I had to do:

declare module "file-saver";

in my typings.d.ts file.

Then, to use it:

// Import
import * as FileSaver from "file-saver";

//Implementation
FileSaver.saveAs(blob, filename);

For reference, these steps are taken from Angular-Cli's steps for installing third-party libraries

Edit 9/27/2017: It appears there is now a type definition for FileSaver.js according to the README instructions, so instead of the

declare module "file-saver"

you just need to

npm install @types/file-saver --save-dev

回答3:

Just doing npm install file-saver --save is a good start. You also need a typescript declaration file (like file-saver.d.ts or typings.d.ts) for this library is in plain javascript. Normally you would get it by doing npm install @types/file-saver but this package is currently outdated.

I have created a file-saver.d.ts for myself – just place it in your source directory.

file-saver.d.ts

declare function saveAs(data: Blob, filename: string, noAutoBOM?: boolean): void;
declare module 'file-saver' {
    export = saveAs;
}

Then you can use saveAs as follows:

your.ts

import saveAs = require('file-saver');
function save() {
    let blob = new Blob(['Hello world!'], { type: 'text/plain;charset=utf-8' });
    saveAs(blob, 'newcontrol.txt');
}

Of course, don't forget to update your loader's configuration.

For SystemJS you need something like this:

/**
 * System configuration for Angular samples
 * Adjust as necessary for your application needs.
 */
(function (global) {
  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: 'app',

      // 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',
      'file-saver':                'npm:file-saver'
    },
    // packages tells the System loader how to load when no filename and/or no extension
    packages: {
      app: {
        main: './main.js',
        defaultExtension: 'js'
      },
      rxjs: {
        defaultExtension: 'js'
      },
      'file-saver': {
        main: './FileSaver.js',
        defaultExtension: 'js'
      }
    }
  });
})(this);