Description

module-alias-jest enables you to setup your module aliases in one place (e.g. your package.json), then use them in both jest tests and elsewhere.

It wraps module-alias, so it also has all of the same requirements and caveats as that package.

Install

# npm
npm install module-alias-jest

# yarn
yarn add module-alias-jest

Usage

// package.json
{
  _aliases: { // ._moduleAliases will also work
    '@root': '.',
    '@utils': './src/utils'
  }
}

// jest.config.js
const aliases = require('module-alias-jest/register')

module.exports = {
  ...,
  moduleNameMapper: aliases.jest
}

// some.test.js
const utils = require('@utils')
describe('utils', () => {...})

// app-entrypoint.js
require('module-alias-jest/register')
const utils = require('@utils')
utils.doSomething()

Notes

• By default, module-alias-jest/register will resolve full paths for your values defined in package.json, relative to the root app path
  • You can disable this by passing the value options.resolve = false, or by programmatically setting aliases using addAlias and addAliases

API

registerAliases

• Registers the aliases defined in your app root's package.json with module-alias,
• root param: project root path to find a package.json
• resolve param: if true, resolve absolute paths for your alias values relative to options.root
• Returns: an aliases object that includes the jest moduleNameMapper object

const { registerAliases } = require('module-alias-jest')

const { node, jest } = registerAliases({
  root: <project root path> // defaults to the consuming project's root path
  resolve: true/false // defaults to true
})

getAliases

• returns the current state of aliases tracked by module-alias-jest

const { getAliases } = require('module-alias-jest')

console.log(getAliases())

getJestAliases

• the same function registerAliases uses to return the jest aliases
• you shouldn't need to call this explicitly (see Usage section), unless you want to customize the way the jest aliases are formatted
• aliasHandler param: a reducing function that formats aliases for the jest aliases map

const { getJestAliases } = require('module-alias-jest')

// this would re-implement the default behavior (equivalent to `getJestAliases()`)
const jestAliases = getJestAliases((aliasMap, aliasKey, aliasPath) => {
  aliasMap[aliasKey + '(.*)'] = aliasPath + '$1'
  return aliasMap
})

module-alias

• module-alias-jest wraps and exports these module-alias functions:
  • addAlias
  • addAliases
  • reset