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

tetsuharuohzeki · tetsuharuohzeki · commit f3c33cd73cd3 · 2016-09-12T13:06:01.000+09:00
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> {

Original file line number	Diff line number	Diff line change
`@@ -50,6 +50,7 @@ export function filter<T>(predicate: (value: T, index: number) => boolean,`
`50`	`50`
`51`	`51`	`export interface FilterSignature<T> {`
`52`	`52`	`(predicate: (value: T, index: number) => boolean, thisArg?: any): Observable<T>;`
	`53`	`+ <S extends T>(predicate: (value: T, index: number) => value is S, thisArg?: any): Observable<S>;`
`53`	`54`	`}`
`54`	`55`
`55`	`56`	`class FilterOperator<T> implements Operator<T, T> {`