fix(ListWrapper): make list slice in dart return empty list if start and end are inverted like JS

itslenny · vsavkin · commit bced3aaa1764 · 2015-09-15T11:42:30.000-07:00
diff --git a/modules/angular2/src/core/facade/collection.dart b/modules/angular2/src/core/facade/collection.dart
@@ -182,6 +182,10 @@ class ListWrapper {
   }
 
   static List slice(List l, [int from = 0, int to]) {
+    //in JS if from > to an empty array is returned
+    if(to != null && from > to) {
+      return [];
+    }
     return l.sublist(_startOffset(l, from), _endOffset(l, to));
   }
 
diff --git a/modules/angular2/test/core/facade/collection_spec.ts b/modules/angular2/test/core/facade/collection_spec.ts
@@ -62,6 +62,9 @@ export function main() {
 
       it('should support negative end',
          () => { expect(ListWrapper.slice(l, -3, -1)).toEqual([2, 3]); });
+
+      it('should return empty list if start is greater than end',
+         () => { expect(ListWrapper.slice(l, 4, 2)).toEqual([]); });
     });
 
     describe('indexOf', () => {

Original file line number	Diff line number	Diff line change
`@@ -182,6 +182,10 @@ class ListWrapper {`
`182`	`182`	`}`
`183`	`183`
`184`	`184`	`static List slice(List l, [int from = 0, int to]) {`
	`185`	`+ //in JS if from > to an empty array is returned`
	`186`	`+ if(to != null && from > to) {`
	`187`	`+ return [];`
	`188`	`+ }`
`185`	`189`	`return l.sublist(_startOffset(l, from), _endOffset(l, to));`
`186`	`190`	`}`
`187`	`191`