feat(limitTo): ignore limit when invalid

BREAKING CHANGE: limitTo changed behavior when limit value is invalid.
Instead of returning empty object/array it returns unchanged input.

Closes #10510

src/ng/filter/limitTo.js

@@ -15,7 +15,8 @@
  * @param {string|number} limit The length of the returned array or string. If the `limit` number
  *     is positive, `limit` number of items from the beginning of the source array/string are copied.
  *     If the number is negative, `limit` number  of items from the end of the source array/string
- *     are copied. The `limit` will be trimmed if it exceeds `array.length`
+ *     are copied. The `limit` will be trimmed if it exceeds `array.length`. If `limit` is undefined,
+ *     the input will be returned unchanged.
  * @returns {Array|string} A new sub-array or substring of length `limit` or less if input array
  *     had less than `limit` elements.
  *
@@ -88,20 +89,16 @@
 */
 function limitToFilter() {
   return function(input, limit) {
-    if (isNumber(input)) input = input.toString();
-    if (!isArray(input) && !isString(input)) return input;
-
     if (Math.abs(Number(limit)) === Infinity) {
       limit = Number(limit);
     } else {
       limit = int(limit);
     }
+    if (isNaN(limit)) return input;
 
-    //NaN check on limit
-    if (limit) {
-      return limit > 0 ? input.slice(0, limit) : input.slice(limit);
-    } else {
-      return isString(input) ? "" : [];
-    }
+    if (isNumber(input)) input = input.toString();
+    if (!isArray(input) && !isString(input)) return input;
+
+    return limit >= 0 ? input.slice(0, limit) : input.slice(limit);
   };
 }

test/ng/filter/limitToSpec.js

@@ -34,20 +34,30 @@ describe('Filter: limitTo', function() {
   });
 
 
-  it('should return an empty array when X cannot be parsed', function() {
-    expect(limitTo(items, 'bogus')).toEqual([]);
-    expect(limitTo(items, 'null')).toEqual([]);
-    expect(limitTo(items, 'undefined')).toEqual([]);
-    expect(limitTo(items, null)).toEqual([]);
-    expect(limitTo(items, undefined)).toEqual([]);
+  it('should return an empty array when X = 0', function() {
+    expect(limitTo(items, 0)).toEqual([]);
+    expect(limitTo(items, '0')).toEqual([]);
   });
 
-  it('should return an empty string when X cannot be parsed', function() {
-    expect(limitTo(str, 'bogus')).toEqual("");
-    expect(limitTo(str, 'null')).toEqual("");
-    expect(limitTo(str, 'undefined')).toEqual("");
-    expect(limitTo(str, null)).toEqual("");
-    expect(limitTo(str, undefined)).toEqual("");
+  it('should return entire array when X cannot be parsed', function() {
+    expect(limitTo(items, 'bogus')).toEqual(items);
+    expect(limitTo(items, 'null')).toEqual(items);
+    expect(limitTo(items, 'undefined')).toEqual(items);
+    expect(limitTo(items, null)).toEqual(items);
+    expect(limitTo(items, undefined)).toEqual(items);
+  });
+
+  it('should return an empty string when X = 0', function() {
+    expect(limitTo(str, 0)).toEqual("");
+    expect(limitTo(str, '0')).toEqual("");
+  });
+
+  it('should return entire string when X cannot be parsed', function() {
+    expect(limitTo(str, 'bogus')).toEqual(str);
+    expect(limitTo(str, 'null')).toEqual(str);
+    expect(limitTo(str, 'undefined')).toEqual(str);
+    expect(limitTo(str, null)).toEqual(str);
+    expect(limitTo(str, undefined)).toEqual(str);
   });