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.


Also supports hooking into calls to process.getBuiltinModule(), which was introduced in Node.js v22.3.0.

Installation

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

Usage

`js
const path = require('path')
const { Hook } = require('require-in-the-middle')

// Hook into the express and mongodb module
new Hook(['express', 'mongodb'], function (exports, name, basedir) {
const 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:

$3

When called a hook object is returned.

Arguments:

- modules <string[]> An optional array of module names to limit which modules
trigger a call of the onrequire callback. If specified, this must be the
first argument. Both regular modules (e.g. react-dom) and
sub-modules (e.g. react-dom/server) can be specified in the array.
- options <Object> An optional object containing fields that change when the
onrequire callback is called. If specified, this must be the second
argument.
- options.internals <boolean> Specifies whether onrequire should be called
when module-internal files are loaded; defaults to false.
- onrequire <Function> The function to call when a module is required.

The onrequire callback will be called the first time a module is
required. The function is called with three arguments:

- exports <Object> The value of the module.exports property that would
normally be exposed by the required module.
- name <string> The name of the module being required. If options.internals
was set to true, the path of module-internal files that are loaded
(relative to basedir) will be appended to the module name, separated by
path.sep.
- basedir <string> The directory where the module is located, or undefined
for core modules.

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

$3

Removes the onrequire callback so that it will not be triggerd by
subsequent calls to require() or process.getBuiltinModule()`.

License

MIT