fliphub-monorepo/modules/mahna/require-path.js

the builder of builders

// https://github.com/mozilla-neutrino/neutrino-dev/blob/master/packages/neutrino/src/requireMiddleware.js
/* eslint-disable global-require*/
const {join} = require('path')

const castToArray = val => (Array.isArray(val) ? val : [val])

function requirePath(path, middleware) {
  try {
    return require(path)
  } catch (exception) {
    if (!/Cannot find module/.test(exception.message)) {
      exception.message = `Neutrino was unable to load the module '${middleware}'. ` +
        `Ensure this module exports a function and is free from errors.\n${exception.message}`
      throw exception
    }

    return undefined
  }
}

module.exports = function requireMiddleware(middleware, options = {}) {
  const root = options.root || process.cwd()

  return castToArray(middleware).map((middleware) => {
    const path = [
      join(root, middleware),
      join(root, 'node_modules', middleware),
    ].find(path => requirePath(path))

    if (!path) {
      throw new Error(`Neutrino cannot find a module with the name or path '${middleware}'. ` +
        'Ensure this module can be found relative to the root of the project.')
    }

    return require(path)
  })
}