mhook

Middleware like hooks for node.js which is useful for building some relations between entities (ODM, ORM, etc).

Installation

npm install mhook

Usage

Define your actions, bind hooks on them, trigger actions. When you trigger an action all binded hooks will be sequentially executed. Be careful, hook function should return promise or call provided callback, otherwise trigger will hang.

var Hook = require('mhook').Hook;


var hook = new Hook(['beforeUpdate', 'afterUpdate', 'afterRemove']);

// add hook with callback
hook.on('beforeUpdate', function(done) {
	// do something, and then say that you done,
	// pass error as first argument to done
	done();
});

// add another hook with promise
hook.on('beforeUpdate', function() {
	return Promise.resolve();
});

// trigger `action` - executes all two hooks
hook.trigger('beforeUpdate', [], function(err) {
	// this function will be called after all
	// hooks done or one of them fail
});

// trigger also return promise
hook.trigger('beforeUpdate', []).then(function(err) {
	// all hooks successfully done
}).catch(function(err) {
	// one of them fail
});

for getting on and trigger methods to your object you can inherits from Hook

var Hook = require('mhook').Hook,
	inherits = require('util').inherits;


function Model() {
	// apply parent cunstructor
	Hook.call(this, ['beforeUpdate', 'afterUpdate', 'afterRemove']);
}

// inherits from Hook
inherits(Model, Hook);

// now we can use `on` and `trigger` as own methods
Model.prototype.update = function(obj, callback) {
	this.trigger('beforeUpdate', [obj], function(err) {
		if (err) {callback(err); return}
		// update
		// trigger afterUpdate, etc
	});
};


var model = new Model();

model.on('beforeUpdate', function(obj, done) {
	console.log('before update object: ', obj);
	done();
});

Hook()

Hook constructor

accepts array of string actions - possible actions which could be used at on and trigger

Hook.on(action:String, hook:Function)

Bind hook on action

Hook.trigger(action:String, hookArgs:Array, [callback]:Function)

Trigger some action with hookArgs (arguments which will be passed to every hook function). If callback (accepts error as first argument) function presents it will be called after hooks execution. Return promise which will be resolved after hooks execution.

Running test

Into cloned repository run npm run test

fleg/node-mhook