ofrobots / require-in-the-middle

Module to hook into the Node.js require function

require-in-the-middle

Hook into the Node.js require function. This allows you to modify modules on-the-fly as they are being required.

Installation

npm install require-in-the-middle --save

Usage

var path = require('path')
var hook = require('require-in-the-middle')

// Hook into the express and mongodb module
hook(['express', 'mongodb'], function (exports, name, basedir) {
  var version = require(path.join(basedir, 'package.json')).version

  console.log('loading %s@%s', name, version)

  // expose the module version as a property on its exports object
  exports._version = version

  // whatever you return will be returned by `require`
  return exports
})

API

The require-in-the-middle module exposes a single function:

function ([modules, ]onrequire) {}

You can optionally supply an array of module names as the first argument to limit which modules will trigger a call of the onrequire callback.

Supply a callback function as the last argument. This function will be called the first time a module is required. The onrequire function is called with three arguments:

• exports - The value of the module.exports property that would normally be exposed by the required module
• name - The name of the module being required
• basedir - The directory of the where the module is located (will be undefined if core module)

Return the value you want the module to expose (normally the exports argument).

License

MIT