feat(store): capture the type of a selector projector function (#1920)

Closes #1908
ngrx · Jun 6, 2019 · 4e39cc1 · 4e39cc1
1 parent d81ddeb
commit 4e39cc1
Showing 1 changed file with 15 additions and 6 deletions.
diff --git a/modules/store/src/selector.ts b/modules/store/src/selector.ts
@@ -12,17 +12,26 @@ export type MemoizeFn = (t: AnyFn) => MemoizedProjection;
 
 export type ComparatorFn = (a: any, b: any) => boolean;
 
-export interface MemoizedSelector<State, Result>
-  extends Selector<State, Result> {
+export type DefaultProjectorFn<T> = (...args: any[]) => T;
+
+export interface MemoizedSelector<
+  State,
+  Result,
+  ProjectorFn = DefaultProjectorFn<Result>
+> extends Selector<State, Result> {
   release(): void;
-  projector: AnyFn;
+  projector: ProjectorFn;
   setResult: (result?: Result) => void;
 }
 
-export interface MemoizedSelectorWithProps<State, Props, Result>
-  extends SelectorWithProps<State, Props, Result> {
+export interface MemoizedSelectorWithProps<
+  State,
+  Props,
+  Result,
+  ProjectorFn = DefaultProjectorFn<Result>
+> extends SelectorWithProps<State, Props, Result> {
   release(): void;
-  projector: AnyFn;
+  projector: ProjectorFn;
   setResult: (result?: Result) => void;
 }