UglifyJS抛出意外的令牌：关键字（const）和node_modules [英] UglifyJS throws unexpected token: keyword (const) with node_modules

问题描述

我开始的一个小项目使用一个节点模块（通过 npm 安装）来声明 const 变量。运行和测试这个项目很好，但是当执行UglifyJS时，browserify失败。

A small project I started make use a node module (installed via npm) that declares const variables. Running and testing this project is well, but browserify fails when UglifyJS is executed.

意外的令牌：关键字（const）

Unexpected token: keyword (const)

这是一个通用的Gulp文件，我已经成功地用于其他一些过去没有这个问题的项目（即没有那个特定的节点模块）。

Here is a generic Gulp file that I have successfully been using for a few other past projects without this issue (i.e. without that particular node module).

'use strict';

const browserify = require('browserify');
const gulp = require('gulp');
const source = require('vinyl-source-stream');
const derequire = require('gulp-derequire');
const buffer = require('vinyl-buffer');
const uglify = require('gulp-uglify');
const sourcemaps = require('gulp-sourcemaps');
const gutil = require('gulp-util');
const path = require('path');
const pkg = require('./package');
const upperCamelCase = require('uppercamelcase');

const SRC_PATH = path.dirname(pkg.main);
const DIST_PATH = path.dirname(pkg.browser);

const INPUT_FILE = path.basename(pkg.main);
const OUTPUT_FILE = path.basename(pkg.browser);

const MODULE_NAME = upperCamelCase(pkg.name);


gulp.task('default', () => {
  // set up the browserify instance on a task basis
  var b = browserify({
    entries: INPUT_FILE,
    basedir: SRC_PATH,
    transform: ['babelify'],
    standalone: MODULE_NAME,
    debug: true
  });

  return b.bundle()
    .pipe(source(OUTPUT_FILE))
    .pipe(buffer())
    .pipe(derequire())
    .pipe(sourcemaps.init({loadMaps: true}))
    .pipe(uglify())
    .on('error', gutil.log)
    .pipe(sourcemaps.write('.'))
    .pipe(gulp.dest(DIST_PATH))
  ;
});

我试过通过替换所有 const 在npm-installed模块中输入 var ，一切都很好。所以我不明白失败。

I have tried fixing this by replace all const to var in that npm-installed module, and everything is fine. So I do not understand the failure.

const 有什么问题？除非有人使用IE10，所有主流浏览器都支持这种语法。

What's wrong with const? Unless someone uses IE10, all major browsers support this syntax.

有没有办法解决这个问题，而无需更改该节点模块？

Is there a way to fix this without requiring a change to that node module?

我暂时（或永久）用 Butternut 并且似乎有效。

I have temporarily (or permanently) replaced UglifyJS with Butternut and seem to work.

推荐答案

2018年11月更新：

使用 terser-webpack-plugin （webpack @ 5将使用此插件进行uglification）

Use terser-webpack-plugin for ES6 (webpack@5 will use this plugin for uglification)

npm install terser-webpack-plugin --save-dev

然后在你的<$中定义c $ c> plugins array

Then define in your plugins array

const TerserPlugin = require('terser-webpack-plugin')

  new TerserPlugin({
    parallel: true,
    terserOptions: {
      ecma: 6,
    },
  }),

Source

这篇关于UglifyJS抛出意外的令牌：关键字（const）和node_modules的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！