Question

我有一个以ES6模块语法开头的摩卡测试文件（test/test.js）：

import {promises as fs} from 'fs'
import stepToD3 from '../src/StepToD3'
import assert from "assert"

此外，我在项目的根目录中有一个babel.config.js文件：

module.exports = {
    presets: [
        "@vue/app",
        "@babel/preset-env"
    ]
}

然后我想使用通过Babel转译的Mocha进行测试。我这样做是使用mocha --require @babel/register test/test.js。但是，在执行过程中的某个地方，此操作失败并显示以下错误：

/home/michael/Programming/cola-step/node_modules/@babel/runtime-corejs2/helpers/esm/asyncToGenerator.js:1
(function (exports, require, module, __filename, __dirname) { import _Promise from "../../core-js/promise";
                                                                     ^^^^^^^^

SyntaxError: Unexpected identifier
    at new Script (vm.js:84:7)
    at createScript (vm.js:264:10)
    at Object.runInThisContext (vm.js:312:10)
    at Module._compile (internal/modules/cjs/loader.js:684:28)
    at Module._compile (/home/michael/Programming/cola-step/node_modules/pirates/lib/index.js:83:24)
    at Module._extensions..js (internal/modules/cjs/loader.js:732:10)
    at Object.newLoader [as .js] (/home/michael/Programming/cola-step/node_modules/pirates/lib/index.js:88:7)
    at Module.load (internal/modules/cjs/loader.js:620:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:560:12)
    at Function.Module._load (internal/modules/cjs/loader.js:552:3)
    at Module.require (internal/modules/cjs/loader.js:657:17)
    at require (internal/modules/cjs/helpers.js:22:18)
    at Object.<anonymous> (/home/michael/Programming/cola-step/test/test.js:7:49)
    at Module._compile (internal/modules/cjs/loader.js:721:30)
    at Module._compile (/home/michael/Programming/cola-step/node_modules/pirates/lib/index.js:83:24)
    at Module._extensions..js (internal/modules/cjs/loader.js:732:10)
    at Object.newLoader [as .js] (/home/michael/Programming/cola-step/node_modules/pirates/lib/index.js:88:7)
    at Module.load (internal/modules/cjs/loader.js:620:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:560:12)
    at Function.Module._load (internal/modules/cjs/loader.js:552:3)
    at Module.require (internal/modules/cjs/loader.js:657:17)
    at require (internal/modules/cjs/helpers.js:22:18)
    at /usr/lib/node_modules/mocha/lib/mocha.js:231:27
    at Array.forEach (<anonymous>)
    at Mocha.loadFiles (/usr/lib/node_modules/mocha/lib/mocha.js:228:14)
    at Mocha.run (/usr/lib/node_modules/mocha/lib/mocha.js:536:10)
    at Object.<anonymous> (/usr/lib/node_modules/mocha/bin/_mocha:573:18)
    at Module._compile (internal/modules/cjs/loader.js:721:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:732:10)
    at Module.load (internal/modules/cjs/loader.js:620:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:560:12)
    at Function.Module._load (internal/modules/cjs/loader.js:552:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:774:12)
    at executeUserCode (internal/bootstrap/node.js:342:17)
    at startExecution (internal/bootstrap/node.js:276:5)
    at startup (internal/bootstrap/node.js:227:5)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:743:3)

如果我使用的是Babel，为什么它为什么无法理解ES6导入语法？怎么了？

Answer 1

在这种情况下，我在NodeJS上使用mocha运行测试，但是我的babel.config.js被设置为为浏览器生成代码。为了解决这个问题，我必须创建两个不同的babel设置，然后在运行适当的命令之前导出正确的NODE_ENV值（例如，NODE_ENV=test mocha --require @babel/register用于测试，NODE_ENV=production用于Webpack生产版本））。

这是我的新babel.config.js：

module.exports = {
    'env': {
        'production': {
            'presets': [
                [
                    '@vue/app',
                    {
                        // "modules": false,
                        'targets': ['ie >= 9']
                    },
                    '@babel/env'
                ]
            ],
            'comments': false
        },
        'test': {
            'presets': [
                [
                    '@babel/env',
                    {'targets': {'node': 'current'}}
                ]
            ]
        }
    }
}

SyntaxError：带有摩卡和babel的意外标识符

1 个答案: