Trying ES6 style import gives 'Cannot use import statement outside a module'

Question

I am trying to write a javascript test in intellij for which I need to import some dependancies and I want to use ES6 style import statements but getting error

/usr/local/bin/node /workspace/rr-sample/node_modules/mocha/bin/_mocha --ui bdd --reporter "/Users/me/Library/Application Support/IntelliJIdea2019.1/NodeJS/js/mocha-intellij/lib/mochaIntellijReporter.js" tests/*.test.js /workspace/rr-sample/tests/App.test.js:3 import chai from 'chai' ^^^^^^  SyntaxError: Cannot use import statement outside a module     at wrapSafe (internal/modules/cjs/loader.js:1043:16)     at Module._compile (internal/modules/cjs/loader.js:1091:27)     at Object.Module._extensions..js (internal/modules/cjs/loader.js:1160:10)     at Module.load (internal/modules/cjs/loader.js:976:32)     at Function.Module._load (internal/modules/cjs/loader.js:884:14)     at Module.require (internal/modules/cjs/loader.js:1016:19)     at require (internal/modules/cjs/helpers.js:69:18)     at /workspace/rr-sample/node_modules/mocha/lib/mocha.js:334:36     at Array.forEach (<anonymous>)     at Mocha.loadFiles (/workspace/rr-sample/node_modules/mocha/lib/mocha.js:331:14)     at Mocha.run (/workspace/rr-sample/node_modules/mocha/lib/mocha.js:809:10)     at Object.exports.singleRun (/workspace/rr-sample/node_modules/mocha/lib/cli/run-helpers.js:108:16)     at exports.runMocha (/workspace/rr-sample/node_modules/mocha/lib/cli/run-helpers.js:142:13)     at Object.exports.handler (/workspace/rr-sample/node_modules/mocha/lib/cli/run.js:292:3)     at Object.runCommand (/workspace/rr-sample/node_modules/yargs/lib/command.js:242:26)     at Object.parseArgs [as _parseArgs] (/workspace/rr-sample/node_modules/yargs/yargs.js:1087:28)     at Object.parse (/workspace/rr-sample/node_modules/yargs/yargs.js:566:25)     at Object.exports.main (/workspace/rr-sample/node_modules/mocha/lib/cli/cli.js:68:6)     at Object.<anonymous> (/workspace/rr-sample/node_modules/mocha/bin/_mocha:10:23)     at Module._compile (internal/modules/cjs/loader.js:1121:30)     at Object.Module._extensions..js (internal/modules/cjs/loader.js:1160:10)     at Module.load (internal/modules/cjs/loader.js:976:32)     at Function.Module._load (internal/modules/cjs/loader.js:884:14)     at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:67:12)     at internal/main/run_main_module.js:17:47  

What exactly is the issue? I found this link (and others) http://xahlee.info/js/js_import_export.html which tells you how to fix this error but in another context which doesn't help me, and it doesn't explain what the problem is.

In case it is helpful here is the code I am using.

//const chai = require("chai"); import chai from 'chai'  const React = require("react"); const expect = chai.expect;  describe('how it works first-time test', () => {   it('checks equality', () => {      const val = false;     expect(val).to.be.false;   });  }); 

Answer 1

The easiest way to run Mocha tests written in ES6 is compiling them on-the-fly using Mocha --require @babel/register option (see https://github.com/mochajs/mocha/wiki/compilers-deprecation#what-should-i-use-instead-then). Of course, you need to make sure to install the corresponding modules and set up the .babelrc accordingly

package.json:

"dependencies": {   "@babel/cli": "^7.7.4",   "@babel/core": "^7.7.4",   "@babel/preset-env": "^7.7.4",   "@babel/register": "^7.7.4", ... } 

.babelrc:

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

See also https://dev.to/bnorbertjs/my-nodejs-setup-mocha--chai-babel7-es6-43ei