small js library to watch objects for changes

The script creates an object on the window with the name 'ObjectObserver'.

• methods
  • observe (object, property, callback)
    • listens for changes of the given property on the given object and invokes the callback with the new value, if the value gets set
    • callbacks only get invoked, if the new value is different from the old one
    • unique callbacks get only added once
  • unobserve (object, property, callback)
    • removes the listeners for the property changes of the given object

var f = {
        foo: 'foo'
    },

    cb = function (newVal) {
        console.log(newVal);
    },

    i = document.getElementById('foo');

ObjectObserver.observe(f, 'foo', cb);

console.log(f.foo) // >> foo
f.foo = 'bar'; // >> bar

ObjectObserver.unobserve(f, 'foo', cb);
f.foo = 'baz'; // >> [no output]

• when deleting an object property which gets observed, the observing of that property gets lost
  • to reenable observing, you have to call ObjectObserver.observe() again