Babel unexpected token import when running mocha tests

Question

The solutions offered in other related questions, such as including the proper presets (es2015) in .babelrc, are already implemented in my project.

I have two projec

Answer 1

I had the same problem. When running tests I realized I actually wanted to stub dependent modules. It's good for unit testing and prevents babel from transforming submodules. So I used proxyquire, namely:

const proxyquire = require('proxyquire').noCallThru()

const myTestedModule = proxyquire('../myTestedModule', {
    'dependentModule1': { //stubbed module1 },
    'dependentModule2': { //stubbed module2 }
})

Answer 2

For Babel <6

The easiest way to solve this problem is:

1. npm install babel-preset-es2015 --save-dev

2. Add .babelrc to the root of the project with contents:

   {
    "presets": [ "es2015" ]
   }
   

Ensure that you are running mocha with the "--compilers js:babel-core/register" parameter.

For Babel6/7+

1. npm install @babel/preset-env --save-dev

2. Add .babelrc to the root of the project with contents:

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

Ensure that you are running mocha with the --compilers js:babel-register (Babel 6) or --compilers js:@babel/register (Babel 7) parameter

For mocha version 7 or later, use --require babel-register or --require @babel/register respectively.

Answer 3

I ran into that same issue. Having tried every other solution on stackoverflow and beyond, adding this simple config on package.json did it for me:

  "babel": {
    "presets": [
      "es2015"
    ]
  }

All my ES6 imports worked after that. By the way, I had this same configuration inside webpack.config.js, but apparently this was the only way to make it work for mocha testing as well.

Hope this helps someone.

Answer 4

I had {"modules": false} in my .babelrc file, like so:

"presets": [
    ["es2015", {"modules": false}],
    "stage-2",
    "react"
]

which was throwing

Unexpected token import

Once i removed it, mocha ran successfully.

Answer 5

You might need to specify the extensions option if you're using TypeScript:

require("@babel/register")({
  extensions: ['.jsx', '.js', '.ts', '.tsx']
})

Answer 6

Well sure you will have that issue, you are using ES6 that mocha don't know

So you are using babel but you don't use it in your test...

Few Solutions:

A. if you running with NPM use

"test": "mocha --compilers js:babel-core/register test*.js"

B. I'm using

"test": "./node_modules/.bin/mocha --compilers js:babel-core/register **/*spec.jsx"

C. From cli:

mocha --compilers js:babel-core/register test*.js

You can read more at http://www.pauleveritt.org/articles/pylyglot/es6_imports/