Require-proxy-mock NPM

require-proxy-mock

Automatically and transparently patches all require calls (Module._load) to return an ES6 Proxy wrapper around the original module's export(s) which can later be mocked/unmocked as required.

Somewhat similar to proxyquire, rewire, and Jest's automock.

Requires Node v6+ (try 10+ if you're getting errors like this)

Install

npm install --save-dev require-proxy-mock

Usage

API

const { mock } = require('require-proxy-mock')

mock(dep, mock)
mock({dep: mock, ...})
mock(Map {dep => mock, ...})

dep [string|regex] Require request of the dependency to mock.
mock Mock that replaces the required dependency.

Example

Important: Require once before loading any other modules:

mocha --require require-proxy-mock **/*.test.js

Then require it as an object in your test(s) and add/remove properties on it with the same key names as the originally required files you want to mock:

main.js - A typical module file; no change required here

const someLib = require('some-lib')
                         ^^^^^^^^ will be mocked
module.exports = someLib

some-lib.js - Dependency that'll be mocked
```
module.exports = () => 'ORIGINAL'
```

main.test.js

const {mock} = require('require-proxy-mock')
const main = require('./main')

describe('main', () => {
  let unmock
  before(() => {
    unmock = mock('some-lib', () => 'CHANGED')
                   ^^^^^^^^ mocked
  })
  it('should mock', () => {
    assert(main(), 'CHANGED')
  })
  after(() => {
    unmock()
  })
})