使用 ES6 样式导入进行 mocha 测试

Question

I'm trying to run a Mocha test with some ES6 style imports in the file but I keep getting the error:

import assert from 'assert';
       ^^^^^^

SyntaxError: Unexpected identifier

I tried to invoke mocha with both mocha --require @babel/register --recursive and mocha --require babel-register --recursive but the error would not go away.

What is the correct way to run ES6 style Mocha tests?

Answer 1

For anyone coming from Google:

You can also install esm: npm i esm --save-dev or use your preferred package manager.

Then pass it as an argument to mocha: mocha 'index.test.js' --require esm

Answer 2

I found the answer to my question here -> https://dev.to/bnorbertjs/my-nodejs-setup-mocha--chai-babel7-es6-43ei

This package.json file

{
  "name": "mochatest",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "mocha --require @babel/register --recursive"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@babel/core": "^7.1.2",
    "@babel/preset-env": "^7.5.4",
    "@babel/register": "^7.4.4",
    "mocha": "^6.1.4"
  },
  "dependencies": {}
}

together with this .babelrc

{
  "presets": ["@babel/preset-env"]
}

solved my problem.

Answer 3

Try Below Code

import { strict as assert } from 'assert';

Or

import * as assert from 'assert';

Hope this helps