azer / Watch Array

watch-array

Lets you subscribe to any changes made by mutator methods on native JavaScript arrays. If you're looking for a safer & complete abstraction: new-list

watchArray = require('watch-array')

people = ['Joe', 'Smith']

watchArray(people, function(update){ // or watchArray.once(people, function(update){

    update.add
    // => { 1: Taylor, 2: Brown }

    update.remove
    // => [0]
    
    update.sort
    // => undefined

})

people.shift()
people.push('Taylor', 'Brown')

Install

$ npm install array

Subscribing To Deeper Changes

You can easily define your custom type of updates and distribute them using the minimalistic pubsub interface mixed to any array that you watch (see new-list for defining native arrays with Pub/Sub by default):

people = [{ name: 'Joe', age: 27 }, { name: 'Smith', age: 19 }]

watchArray(people, function(update){
    
  if (update.person) {

    update.index
    // => 1
    update.person
    // => { name: 'Smith', age: 20 }

  }
  
})

people[1].age = 20

people.publish({ person: people[1], index: 1 })

How It Works?

• It mixes the given array with new-pubsub.
• It overrides mutable methods like push, splice etc to emit the changes.

Caveats

Following changes won't be catched;

people[people.length] = "Fred";
people[0] = "Barney";
delete people[0];