Babel unexpected token import when running mocha tests

It seems the only solution is to explicitly include:

require('babel-core/register')({
  ignore: /node_modules/(?!ProjectB)/
}); 

in a test helper file, and pass that along to mocha in my test command:

mocha --require ./test/testHelper.js...

---

The final solution:

Add registerBabel.js: a separate file whose job is to require babel-core/register...

require('babel-core/register')({
  ignore: /node_modules/(?!ProjectB)/
});

Add an entry.js if your application also relies on babel-node. This acts as a wrapper for your es6 containing application.

require('./registerBabel');
require('./server'); // this file has some es6 imports

You would then run your application with node entry

For mocha testing, testHelper.js should require registerBabel.js as well to initialize babel support at run time.

require('./registerBabel');

And run your mocha tests with mocha --require ./testHelper.js '+(test)/**/*Spec.js'

This will recursively test any file ending in "Spec.js" within "./test". Substitute the pattern with one matching the specs in your project.

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.