Avoid polluting Array.prototype with new enumerable properties

This way, when enumerating with for(var i in array) the new "fill" and "indexOf" will not show up as array elements.
sonthanhdan · Mar 15, 2018 · 42032e7 · 42032e7
1 parent ad123be
commit 42032e7
Showing 1 changed file with 56 additions and 51 deletions.
diff --git a/lib/polyfill.js b/lib/polyfill.js
@@ -48,74 +48,79 @@ if (!Object.assign) {
  */
 /* istanbul ignore next */
 if (!Array.prototype.indexOf) {
-    Array.prototype.indexOf = function(searchElement, fromIndex) {
-        var k;
+    Object.defineProperty(Array.prototype, "indexOf", {
+		value: function(searchElement, fromIndex) {
+			var k;
 
-        if (this === null) {
-            throw new TypeError('"this" is null or not defined');
-        }
+			if (this === null) {
+				throw new TypeError('"this" is null or not defined');
+			}
 
-        var O = Object(this);
-        var len = O.length >>> 0;
+			var O = Object(this);
+			var len = O.length >>> 0;
 
-        if (len === 0) {
-            return -1;
-        }
+			if (len === 0) {
+				return -1;
+			}
 
-        var n = +fromIndex || 0;
+			var n = +fromIndex || 0;
 
-        if (Math.abs(n) === Infinity) {
-            n = 0;
-        }
+			if (Math.abs(n) === Infinity) {
+				n = 0;
+			}
 
-        if (n >= len) {
-            return -1;
-        }
+			if (n >= len) {
+				return -1;
+			}
 
-        k = Math.max(n >= 0 ? n : len - Math.abs(n), 0);
+			k = Math.max(n >= 0 ? n : len - Math.abs(n), 0);
 
-        while (k < len) {
-            if (k in O && O[k] === searchElement) {
-                return k;
-            }
+			while (k < len) {
+				if (k in O && O[k] === searchElement) {
+					return k;
+				}
 
-            k++;
-        }
+				k++;
+			}
 
-        return -1;
-    };
+			return -1;
+		}
+	});
 }
 
 /**
  * @external {Array.fill} https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array/fill
  */
 /* istanbul ignore next */
 if (!Array.prototype.fill) {
-    Array.prototype.fill = function(value) {
-        if (this === null) {
-            throw new TypeError('this is null or not defined');
-        }
-
-        var O = Object(this);
-        var len = O.length >>> 0;
-        var start = arguments[1];
-        var relativeStart = start >> 0;
-        var k = relativeStart < 0 ?
-            Math.max(len + relativeStart, 0) :
-            Math.min(relativeStart, len);
-        var end = arguments[2];
-        var relativeEnd = end === undefined ?
-            len : end >> 0;
-        var final = relativeEnd < 0 ?
-            Math.max(len + relativeEnd, 0) :
-            Math.min(relativeEnd, len);
-        while (k < final) {
-            O[k] = value;
-            k++;
-        }
-
-        return O;
-    };
+    Object.defineProperty(Array.prototype, "fill", {
+		value: function(value) {
+			if (this === null) {
+				throw new TypeError('this is null or not defined');
+			}
+
+			var O = Object(this);
+			var len = O.length >>> 0;
+			var start = arguments[1];
+			var relativeStart = start >> 0;
+			var k = relativeStart < 0 ?
+				Math.max(len + relativeStart, 0) :
+				Math.min(relativeStart, len);
+			var end = arguments[2];
+			var relativeEnd = end === undefined ?
+				len : end >> 0;
+			var final = relativeEnd < 0 ?
+				Math.max(len + relativeEnd, 0) :
+				Math.min(relativeEnd, len);
+			while (k < final) {
+				O[k] = value;
+				k++;
+			}
+
+			return O;
+		}
+	});
+
 }
 
 /**