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Object watch polyfill
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/* | |
* 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; | |
} | |
}); | |
} |
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