Merge pull request #16 from couzic/filter-not-null

#13 Make filterNotNull() return a Sequence<T> instead of T | null

Author: winterbe

src/filterNotNull.ts

@@ -7,8 +7,8 @@ export class FilterNotNull {
      *
      * @returns {Sequence<T>}
      */
-    filterNotNull<T>(this: Sequence<T>): Sequence<T> {
-        return this.filter(it => it !== null);
+    filterNotNull<T>(this: Sequence<T | null>): Sequence<T> {
+        return this.filter(it => it !== null) as Sequence<T>;
     }
 
 }