diffback

Fire callbacks whenever properties of an object change.

No observers etc. As performant as changing the value and manually executing the callbacks.

Install

npm install diffback

Attach callbacks

var diffback = require('diffback');
function print(value) {
  console.log('Executing: ', value);
}

var obj = {
  a: 1,
  b: 2
};


diffback(obj, 'a', print);

obj.a = 100;

Remove callbacks

diffback.remove(obj, 'a', print); // Removes print callback

// If no callback is specified then all callbacks are removed.
diffback.remove(obj, 'a'); // Removes all callbacks

Example

var diffback = require('diffback');

function print(newValue, oldValue) {
  console.log(newValue, oldValue);
}
var object = {
  a: 10,
  b: "hello"
};

diffback(object, 'z', print);

object.z = 100; // Prints: 100 (new value) undefined (old value)

object.z = 200; // Prints: 200 (new value) 100 (old value)

diffback.remove(object, 'z', print); // removes print callback