带有Gulp的ES6导入模块

Question

我正在尝试将我的ES6模块导入到一个文件中并运行Gulp来连接并缩小文件.我遇到了一个ReferenceError:在all.js(已编译)第3行没有定义require.我用gulp-babel编译了代码.

我的js文件是:

cart.js:

class Cart{
  constructor(){
    this.cart = [];
    this.items = items = [{
        id: 1,
        name: 'Dove Soap',
        price: 39.99
    },{
        id: 2,
        name: 'Axe Deo',
        price: 99.99
    }];
  }


  getItems(){
    return this.items;
  }


}

export {Cart};

app.js:

import {Cart} from 'cart.js';

let cart = new Cart();

console.log(cart.getItems());

gulpfile.js:

"use strict";

let gulp = require('gulp');
let jshint = require('gulp-jshint');
let concat = require('gulp-concat');
let uglify = require('gulp-uglify');
let rename = require('gulp-rename');
let babel = require('gulp-babel');


// Lint Task
gulp.task('lint', function() {
    return gulp.src('js/*.js')
        .pipe(jshint())
        .pipe(jshint.reporter('default'));
});


// Concatenate & Minify JS
gulp.task('scripts', function() {
    return gulp.src('js/*.js')
        .pipe(babel({
            presets: ['env']
        }))
        .pipe(concat('all.js'))
        .pipe(gulp.dest('dist'))
        .pipe(rename('all.min.js'))
        .pipe(uglify().on('error', function(e){
          console.dir(e);
        }))
        .pipe(gulp.dest('dist/js'));
});

// Default Task
gulp.task('default', ['lint','scripts']);

app.js(transpiled):

'use strict';

var _cart = require('cart.js'); //Uncaught ReferenceError: require is not defined

var cart = new _cart.Cart();

console.log(cart.getItems());
'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

var Cart = function () {
  function Cart() {
    _classCallCheck(this, Cart);

    this.cart = [];
    this.items = items = [{
      id: 1,
      name: 'Dove Soap',
      price: 39.99
    }, {
      id: 2,
      name: 'Axe Deo',
      price: 99.99
    }];
  }

  _createClass(Cart, [{
    key: 'getItems',
    value: function getItems() {
      return this.items;
    }
  }]);

  return Cart;
}();exports.Cart = Cart;

Answer 1

Rollup是处理 ES6 模块的一个很好的打包器。它具有内置的原生 ES6 模块支持，因此与 Browserify 不同，它不需要使用 Babel。

这是一个使用 Rollup 的 Gulp 4 配置：

// gulp.js file in the root folder

var gulp = require('gulp');
var sourcemaps = require('gulp-sourcemaps');
var source = require('vinyl-source-stream');
var buffer = require('vinyl-buffer');
var rollup = require('@rollup/stream');

// *Optional* Depends on what JS features you want vs what browsers you need to support
// *Not needed* for basic ES6 module import syntax support
var babel = require('@rollup/plugin-babel');

// Add support for require() syntax
var commonjs = require('@rollup/plugin-commonjs');

// Add support for importing from node_modules folder like import x from 'module-name'
var nodeResolve = require('@rollup/plugin-node-resolve');

// Cache needs to be initialized outside of the Gulp task 
var cache;

gulp.task('js', function() {
  return rollup({
      // Point to the entry file
      input: './app.js',

      // Apply plugins
      plugins: [babel(), commonjs(), nodeResolve()],

      // Use cache for better performance
      cache: cache,

      // Note: these options are placed at the root level in older versions of Rollup
      output: {

        // Output bundle is intended for use in browsers
        // (iife = "Immediately Invoked Function Expression")
        format: 'iife',

        // Show source code when debugging in browser
        sourcemap: true

      }
    })
    .on('bundle', function(bundle) {
      // Update cache data after every bundle is created
      cache = bundle;
    })
    // Name of the output file.
    .pipe(source('bundle.js'))
    .pipe(buffer())

    // The use of sourcemaps here might not be necessary, 
    // Gulp 4 has some native sourcemap support built in
    .pipe(sourcemaps.init({loadMaps: true}))
    .pipe(sourcemaps.write('.'))
 
    // Where to send the output file
    .pipe(gulp.dest('./build/js'));
});
 
gulp.task('js:watch', function(done){
  gulp.watch(['./source/**/*.js'], gulp.series('js'));
  done();
})
 
gulp.task('default', gulp.series('js', 'js:watch'));

Answer 2

您需要一个像Webpack或Browserify这样的捆绑器才能使用ES6导入.Babel只能将ES6代码编译为ES5(原生JS).

Webpack和Browserify都为gulp制作了食谱:

• http://webpack.github.io/docs/usage-with-gulp.html
• https://github.com/gulpjs/gulp/tree/master/docs/recipes

希望这可以帮助.

Answer 3

如果上述解决方案不适合您，请尝试gulp-include。

它使用类似于链轮或套筒的指令。指令是文件中的注释，gulp-include 将其识别为命令。

用法

gulpfile.js：

const gulp = require('gulp')
const include = require('gulp-include')
 
exports.scripts = function (done) {
  gulp.src('source/js/entry.js')
    .pipe(include())
      .on('error', console.log)
    .pipe(gulp.dest('dist/js'))
}

应用程序.js：

//=require ./js/cart.js
//=include ./js/cart.js