function listenArrayEvents(array, listener) {
		if (array._chartjs) {
			array._chartjs.listeners.push(listener);
			return;
		}

		Object.defineProperty(array, '_chartjs', {
			configurable: true,
			enumerable: false,
			value: {
				listeners: [listener]
			}
		});

		arrayEvents.forEach(function(key) {
			var method = 'onData' + key.charAt(0).toUpperCase() + key.slice(1);
			var base = array[key];

			Object.defineProperty(array, key, {
				configurable: true,
				enumerable: false,
				value: function() {
					var args = Array.prototype.slice.call(arguments);
					var res = base.apply(this, args);

					helpers.each(array._chartjs.listeners, function(object) {
						if (typeof object[method] === 'function') {
							object[method].apply(object, args);
						}
					});

					return res;
				}
			});
		});
	}
Hooks the array methods that add or remove values ('push', pop', 'shift', 'splice',
'unshift') and notify the listener AFTER the array has been altered. Listeners are
called on the 'onData*' callbacks (e.g. onDataPush, etc.) with same arguments.