superdata/src/model/prop.js

A lightweight data layer module motivated by extjs' data layer. It can be used with any client-side framework.

/*jslint node: true */
"use strict";

module.exports = function createProp(obj, name, config) {
	//should be called field
	config = config || {};

	var initialValue = config.value;
	var value = initialValue;
	var lastValue = value;

	Object.defineProperty(obj, name, {
		enumerable: true,
		configurable: false,

		set: set,
		get: get
	});

	function set(newVal) {
		if (newVal === value) {
			return;
		}

		if (typeof config.beforeChange === "function") {
			config.beforeChange({lastValue: lastValue, value: value, newValue: newVal, initialValue: initialValue});
		}

		lastValue = value;
		value = newVal;

		if (typeof config.afterChange === "function") {
			config.afterChange({lastValue: lastValue, value: value, newValue: newVal, initialValue: initialValue});
		}
	}

	function get() {
		return value;
	}

	return obj;
};