CODEWITHSUNDEEP
javascriptmocha.jsbabeljs
shock_one
shock_one

Reputation: 5925

Can't require a module while using Mocha with Babel compiler

I have two files: test.js that contains

var Buffer = require('./Buffer');

and Buffer.js with

this.foo

when I run them with mocha test.js, everything works fine, but running mocha --compilers js:babel/register test.js generates the following error

TypeError: Cannot read property 'foo' of undefined
at Object.<anonymous> (/path/Buffer.js:1:1)
at Module._compile (module.js:460:26)
at normalLoader (/path/node_modules/babel/node_modules/babel-core/lib/babel/api/register/node.js:150:5)
at Object.require.extensions.(anonymous function) [as .js] (/path/node_modules/babel/node_modules/babel-core/lib/babel/api/register/node.js:163:7)
at Module.load (module.js:355:32)
at Function.Module._load (module.js:310:12)
at Module.require (module.js:365:17)
at require (module.js:384:17)
at Object.<anonymous> (/path/parser_test.js:2:14)
at Module._compile (module.js:460:26)
at normalLoader (/path/node_modules/babel/node_modules/babel-core/lib/babel/api/register/node.js:150:5)
at Object.require.extensions.(anonymous function) [as .js] (/path/node_modules/babel/node_modules/babel-core/lib/babel/api/register/node.js:163:7)
at Module.load (module.js:355:32)
at Function.Module._load (module.js:310:12)
at Module.require (module.js:365:17)
at require (module.js:384:17)
at /path/node_modules/mocha/lib/mocha.js:192:27
at Array.forEach (native)
at Mocha.loadFiles (/path/node_modules/mocha/lib/mocha.js:189:14)
at Mocha.run (/path/node_modules/mocha/lib/mocha.js:422:31)
at Object.<anonymous> (/path/node_modules/mocha/bin/_mocha:398:16)
at Module._compile (module.js:460:26)
at Object.Module._extensions..js (module.js:478:10)
at Module.load (module.js:355:32)
at Function.Module._load (module.js:310:12)
at Function.Module.runMain (module.js:501:10)
at startup (node.js:129:16)
at node.js:814:3

Why is it happening that this is undefined when I require a module? Please let me know if you need any additional information to reproduce the error.

I use babel 5.5.0 and mocha 2.2.5.

Upvotes: 2

Views: 1080

Answers (1)

Mark Rousskov
Mark Rousskov

Reputation: 971

Babel expects that the input it is given is an ES6/ES2015 module. In modules, top-level this is undefined by the specification.

babel --blacklist strict script.js will allow you to disable this behavior, but this is not according to the specification, so this probably isn't the best idea. You can use global instead to access the global object in node, as an alternative.

For more information, see the documentation.

Upvotes: 1

Related Questions