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object.watch

Observe changes on object properties.

Verzia zo dňa 01.10.2014. Pozri najnovšiu verziu.

Tento skript by nemal byť nainštalovaný priamo. Je to knižnica pre ďalšie skripty, ktorú by mali používať cez meta príkaz // @require https://update.greasyfork.org/scripts/5314/19640/objectwatch.js 

/*
    * object.watch polyfill
    *
    * 2012-04-03
    *
    * By Eli Grey, http://eligrey.com
    * Public Domain.
    * NO WARRANTY EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.
    *
*/

// object.watch
if (!Object.prototype.watch) {
    Object.defineProperty(Object.prototype, "watch", {
        enumerable: false,
        configurable: true,
        writable: false,
        value: function(prop, handler) {
            var oldval = this[prop],
                newval = oldval,
                getter = function() {
                    return newval;
                },
                setter = function(val) {
                    oldval = newval;
                    return newval = handler.call(this, prop, oldval, val);
                };
            if (delete this[prop]) { // can't watch constants
                Object.defineProperty(this, prop, {
                    get: getter,
                    set: setter,
                    enumerable: true,
                    configurable: true
                });
            }
        }
    });
}

// object.unwatch
if (!Object.prototype.unwatch) {
    Object.defineProperty(Object.prototype, "unwatch", {
        enumerable: false,
        configurable: true,
        writable: false,
        value: function(prop) {
            var val = this[prop];
            delete this[prop]; // remove accessors
            this[prop] = val;
        }
    });
}