denude
All that is hidden shall be revealed
Although testing private members is considered an antipattern, sometimes you really, really need to. Denude makes it easy to require functions and variables from the top scope of a module.
Usage
Module you want to test:
const format = let prefix = 'Hello, ' { return } { return } moduleexports = greet helloWorld
Test file:
const denude = const helloWorld greet: publicGreet = // public partsconst format prefix greet = // private parts console // trueconsole // Hello, World!
Notice that denude works independently from require. It means that require('./module')
and denude('./module')
will return different instances of all the members of the module:
const required = const publicDenude = const privateDenude = console // falseconsole // true
Overriding require
You can use require('denude/register')
to patch the native require globally. After that, any require that is passed a path with the ?private
prefix will return the private members instead of the exports.
Example:
const helloWorld = // public partsconst format prefix greet = // private parts
This technique is useful with testing frameworks like mocha and ava that allow requiring modules on run:
mocha --require denude/register test