Function forOwn

test/json3.js:231–291

(object, callback)

      // Internal: Normalizes the `for...in` iteration algorithm across
      // environments. Each enumerated key is yielded to a `callback` function.
      var forOwn = function (object, callback) {
        var size = 0, Properties, members, property;

        // Tests for bugs in the current environment's `for...in` algorithm. The
        // `valueOf` property inherits the non-enumerable flag from
        // `Object.prototype` in older versions of IE, Netscape, and Mozilla.
        (Properties = function () {
          this.valueOf = 0;
        }).prototype.valueOf = 0;

        // Iterate over a new instance of the `Properties` class.
        members = new Properties();
        for (property in members) {
          // Ignore all properties inherited from `Object.prototype`.
          if (isProperty.call(members, property)) {
            size++;
          }
        }
        Properties = members = null;

        // Normalize the iteration algorithm.
        if (!size) {
          // A list of non-enumerable properties inherited from `Object.prototype`.
          members = ["valueOf", "toString", "toLocaleString", "propertyIsEnumerable", "isPrototypeOf", "hasOwnProperty", "constructor"];
          // IE <= 8, Mozilla 1.0, and Netscape 6.2 ignore shadowed non-enumerable
          // properties.
          forOwn = function (object, callback) {
            var isFunction = getClass.call(object) == functionClass, property, length;
            var hasProperty = !isFunction && typeof object.constructor != "function" && objectTypes[typeof object.hasOwnProperty] && object.hasOwnProperty || isProperty;
            for (property in object) {
              // Gecko <= 1.0 enumerates the `prototype` property of functions under
              // certain conditions; IE does not.
              if (!(isFunction && property == "prototype") && hasProperty.call(object, property)) {
                callback(property);
              }
            }
            // Manually invoke the callback for each non-enumerable property.
            for (length = dontEnums.length; property = dontEnums[--length];) {
              if (hasProperty.call(object, property)) {
                callback(property);
              }
            }
          };
        } else {
          // No bugs detected; use the standard `for...in` algorithm.
          forOwn = function (object, callback) {
            var isFunction = getClass.call(object) == functionClass, property, isConstructor;
            for (property in object) {
              if (!(isFunction && property == "prototype") && isProperty.call(object, property) && !(isConstructor = property === "constructor")) {
                callback(property);
              }
            }
            // Manually invoke the callback for the `constructor` property due to
            // cross-environment inconsistencies.
            if (isConstructor || isProperty.call(object, (property = "constructor"))) {
              callback(property);
            }
          };