Object.defineProperty

defineProperty.js

// ES 15.2.3.6 Object.defineProperty ( O, P, Attributes )
// Partial support for most common case - getters, setters, and values
!(function() {
  if (!Object.defineProperty ||
      !(function () { try { Object.defineProperty({}, 'x', {}); return true; } catch (e) { return false; } } ())) {
    var orig = Object.defineProperty;
    Object.defineProperty = function (o, prop, desc) {
      // In IE8 try built-in implementation for defining properties on DOM prototypes.
      if (orig) { try { return orig(o, prop, desc); } catch (e) {} }

      if (o !== Object(o)) { throw TypeError("Object.defineProperty called on non-object"); }
      if (Object.prototype.__defineGetter__ && ('get' in desc)) {
        Object.prototype.__defineGetter__.call(o, prop, desc.get);
      }
      if (Object.prototype.__defineSetter__ && ('set' in desc)) {
        Object.prototype.__defineSetter__.call(o, prop, desc.set);
      }
      if ('value' in desc) {
        o[prop] = desc.value;
      }
      return o;
    };
  }
}());