if statement parsing

assets/JS_INIT.js

@@ -302,3 +302,98 @@ if (!Array.prototype.map) {
         return A;
     };
 }
+// Production steps of ECMA-262, Edition 5, 15.4.4.21
+// Reference: http://es5.github.io/#x15.4.4.21
+// https://tc39.github.io/ecma262/#sec-array.prototype.reduce
+if (!Array.prototype.reduce) {
+    Object.defineProperty(Array.prototype, 'reduce', {
+        value: function(callback /*, initialValue*/) {
+            if (this === null) {
+                throw new TypeError( 'Array.prototype.reduce ' +
+                    'called on null or undefined' );
+            }
+            if (typeof callback !== 'function') {
+                throw new TypeError( callback +
+                    ' is not a function');
+            }
+
+            // 1. Let O be ? ToObject(this value).
+            var o = Object(this);
+
+            // 2. Let len be ? ToLength(? Get(O, "length")).
+            var len = o.length >>> 0;
+
+            // Steps 3, 4, 5, 6, 7
+            var k = 0;
+            var value;
+
+            if (arguments.length >= 2) {
+                value = arguments[1];
+            } else {
+                while (k < len && !(k in o)) {
+                    k++;
+                }
+
+                // 3. If len is 0 and initialValue is not present,
+                //    throw a TypeError exception.
+                if (k >= len) {
+                    throw new TypeError( 'Reduce of empty array ' +
+                        'with no initial value' );
+                }
+                value = o[k++];
+            }
+
+            // 8. Repeat, while k < len
+            while (k < len) {
+                // a. Let Pk be ! ToString(k).
+                // b. Let kPresent be ? HasProperty(O, Pk).
+                // c. If kPresent is true, then
+                //    i.  Let kValue be ? Get(O, Pk).
+                //    ii. Let accumulator be ? Call(
+                //          callbackfn, undefined,
+                //          « accumulator, kValue, k, O »).
+                if (k in o) {
+                    value = callback(value, o[k], k, o);
+                }
+
+                // d. Increase k by 1.
+                k++;
+            }
+
+            // 9. Return accumulator.
+            return value;
+        }
+    });
+}
+// Production steps of ECMA-262, Edition 5, 15.4.4.22
+// Reference: http://es5.github.io/#x15.4.4.22
+if ('function' !== typeof Array.prototype.reduceRight) {
+    Array.prototype.reduceRight = function(callback /*, initialValue*/) {
+        'use strict';
+        if (null === this || 'undefined' === typeof this) {
+            throw new TypeError('Array.prototype.reduce called on null or undefined');
+        }
+        if ('function' !== typeof callback) {
+            throw new TypeError(callback + ' is not a function');
+        }
+        var t = Object(this), len = t.length >>> 0, k = len - 1, value;
+        if (arguments.length >= 2) {
+            value = arguments[1];
+        } else {
+            while (k >= 0 && !(k in t)) {
+                k--;
+            }
+            if (k < 0) {
+                throw new TypeError('Reduce of empty array with no initial value');
+            }
+            value = t[k--];
+        }
+        for (; k >= 0; k--) {
+            if (k in t) {
+                value = callback(value, t[k], k, t);
+            }
+        }
+        return value;
+    };
+}
+