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Author message:

this library is no longer maintained

poison

Allows tinkering with node's module loading system if you really see no other way.

You can intercept require calls to named modules and alter it's exports, e.g. to facade require('debug') with your own logging facility.

Quickstart

var poison = require('poison');
 
// redirect all debug logging library calls directly to console.log
function myCustomDebug(name) {
    return console.log.bind(console, name + ':');
}
 
// apply redirects to new modules loaded by require('debug')
poison.addHook('debug', function(moduleName, mod) {
    mod.exports = myCustomDebug;
});
 
// apply redirects to modules which were already loaded
poison.getModulesByName('debug').forEach(function(mod) {
    mod.exports = myCustomDebug;
});
 
 
var debug = require('debug')('test');
debug('some output');
// outputs 'test: some output'

Usage

addHook(moduleName, hook(moduleName, mod))

Adds a hook function which will be called when a new module with the given name was loaded.

Does not work for native node.js modules, e.g. console and util.

Parameters

• moduleName - The name of the module to intercept, e.g. debug (as passed to require()). Paths are not supported.

• hook(moduleName, mod) - Function called after a new module matching moduleName was loaded.

  • moduleName - The name of the hooked module will be passed again so you can use the same hook function for different names.

  • mod - The module's module object. Feel free to change its exports property.

getModulesByName(moduleName)

Returns an array of all modules which were loaded with the given module name.

Does work for native modules, but you should require() them first to make sure they are loaded.

Parameters

• moduleName - The name of the module to intercept, e.g. debug (as passed to require()). Paths are not supported.

removeHook(moduleName, hook)

Removes a hook previously added using addHook(moduleName, hook).

Parameters

• moduleName - Same module name as passed to addHook(moduleName, hook).

• hook - Same function as passed to addHook(moduleName, hook).

Warning

If you create a project which intercepts foreign modules you should always feature-test these modules first. Different modules (e.g. private ones) may share the same name. Different versions of the same module may also be loaded.

poison uses node.js internals to intercept module loading which may change with any new release and thus break this library. poison is designed to feature-test these internals and if they change in an unexpected way then all of its methods become no-ops and it will issue a warning on the console.

Limitations

You can only intercept modules which

• are loaded by name instead of by path (i.e. debug but not ./debug) and
• were loaded after the poison module (except native node.js modules like console and util).

If poison was loaded multiple times, getModulesByName() returns all modules loaded after the first posion module was loaded.

You should call require('poison') as early as possible in your project or you may miss some modules.

Installation

$ npm install poison

Testing

$ npm install
$ npm test

License

MIT