feat(filter): Observable<T>.filter() can take type guard as the predi…

…cate function
ReactiveX · Sep 16, 2016 · d62fbf0 · d62fbf0
1 parent 36c7676
commit d62fbf0
Showing 1 changed file with 1 addition and 0 deletions.
diff --git a/src/operator/filter.ts b/src/operator/filter.ts
@@ -50,6 +50,7 @@ export function filter<T>(predicate: (value: T, index: number) => boolean,
 
 export interface FilterSignature<T> {
   (predicate: (value: T, index: number) => boolean, thisArg?: any): Observable<T>;
+  <S extends T>(predicate: (value: T, index: number) => value is S, thisArg?: any): Observable<S>;
 }
 
 class FilterOperator<T> implements Operator<T, T> {