mocha.opts not working with babel-register

Question

This is my mocha.opts file:

--require babel-polyfill
--require jsdom-global/register
--compilers js:babel-register
--watch
--recursive
--bail
--check-leaks
--reporter spec

This is my .babelrc file, I am using the env preset which transpiles based on the targets provided:

{
  "presets":[
    "react",
    [
      "env",
      {
        "targets":{
          "chrome":54,
          "node":true
        }
      }
    ]
  ],
  "plugins":[
    "transform-class-properties",
    ["transform-object-rest-spread", {
        "useBuiltIns":true
      }
    ]
  ]
}

I find that when I run mocha, node objects violently to the use of import which works correctly in my code:

/* eslint-env node, mocha*/
import chai, { expect } from 'chai';
import { shallow, mount } from 'enzyme';
import chaiEnzyme from 'chai-enzyme';
chai.use(chaiEnzyme());

describe('EllipsisText', function(){
  it('exists', function() {
    expect(EllipsisText).to.exist;
  });
});

This is the error that mocha throws:

/home/vamsi/Do/css-in-js-test/test/EllipsisText.js:2
import chai, { expect } from 'chai';
^^^^^^
SyntaxError: Unexpected token import
    at Object.exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:513:28)
    at Object.Module._extensions..js (module.js:550:10)
    at Module.load (module.js:458:32)
    at tryModuleLoad (module.js:417:12)
    at Function.Module._load (module.js:409:3)
    at Module.require (module.js:468:17)
    at require (internal/module.js:20:19)
    at /home/vamsi/.nvm/v6.2.0/lib/node_modules/mocha/lib/mocha.js:220:27
    at Array.forEach (native)
    at Mocha.loadFiles (/home/vamsi/.nvm/v6.2.0/lib/node_modules/mocha/lib/mocha.js:217:14)
    at Mocha.run (/home/vamsi/.nvm/v6.2.0/lib/node_modules/mocha/lib/mocha.js:469:10)
    at Object.<anonymous> (/home/vamsi/.nvm/v6.2.0/lib/node_modules/mocha/bin/_mocha:404:18)
    at Module._compile (module.js:541:32)
    at Object.Module._extensions..js (module.js:550:10)
    at Module.load (module.js:458:32)
    at tryModuleLoad (module.js:417:12)
    at Function.Module._load (module.js:409:3)
    at Function.Module.runMain (module.js:575:10)
    at startup (node.js:160:18)
    at node.js:449:3

score 2 · Accepted Answer · edited May 23 '17 at 12:13

2

When using babel, mocha needs to be run like this:

mocha --compilers js:babel-core/register

Related: Running Mocha + Istanbul + Babel
More detail: http://jamesknelson.com/testing-in-es6-with-mocha-and-babel-6/

edited May 23 '17 at 12:13

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answered Nov 14 '16 at 01:27

Lance

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Just a note to say that the `--compilers` option is being depreciated. The correct format is now: `mocha --require babel-core/register` https://github.com/mochajs/mocha/wiki/compilers-deprecation – Gary Doublé Mar 26 '18 at 23:48

mocha.opts not working with babel-register

1 Answers1