ecmascript-6 - REPL 支持 babel-node es6 "Modules aren' t"

Question

babel-preset-es2015已安装，并且可以使用 es6 功能，如下面 let a = 2; .
但无法使用 es6 模块功能 import fs from 'fs'如下:

$ babel-node --presets es2015
> let a = 2;
'use strict'
> a
2
> import fs from 'fs';
SyntaxError: repl: Modules aren't supported in the REPL
import fs from 'fs';  
    at File.buildCodeFrameError (/usr/lib/node_modules/babel-cli/node_modules/babel-core/lib/transformation/file/index.js:407:15)
    at NodePath.buildCodeFrameError (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/path/index.js:149:26)
    at PluginPass.ModuleDeclaration (/usr/lib/node_modules/babel-cli/lib/_babel-node.js:78:20)
    at newFn (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/visitors.js:262:19)
    at NodePath._call (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/path/context.js:63:18)
    at NodePath.call (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/path/context.js:47:17)
    at NodePath.visit (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/path/context.js:93:12)
    at TraversalContext.visitQueue (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/context.js:152:16)
    at TraversalContext.visitMultiple (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/context.js:110:17)
    at TraversalContext.visit (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/context.js:182:19)

那么有什么问题呢？
谢谢!

Answer 1

错误消息正是它所说的。您不能在 REPL 中使用 ES6 模块语法，它不受支持。您可以创建一个小型适配器，以 ES6 形式导入并以 CommonJS 形式导出:

# es6-to-common.js
import MyThing from './somewhere';
module.exports = MyThing;

现在在你平常的 babel-node里面迅速的:

> MyThing = require('./es6-to-common')