fix(store): memoize selector arguments (#1393)

The arguments weren't being memoized when the result of the selector was equal to its previous result. This fix moves the memoization of the arguments before the check if the results are equal.

Closes #1389

Author: timdeschryver

modules/store/spec/selector.spec.ts

@@ -90,6 +90,7 @@ describe('Selectors', () => {
       selector(firstState);
       selector(firstState);
       selector(secondState);
+      selector(secondState);
 
       expect(incrementOne).toHaveBeenCalledTimes(2);
       expect(incrementTwo).toHaveBeenCalledTimes(2);
@@ -201,6 +202,7 @@ describe('Selectors', () => {
       selector(firstState, props);
       selector(firstState, props);
       selector(secondState, props);
+      selector(secondState, props);
 
       expect(counter).toBe(2);
       expect(projectFn).toHaveBeenCalledTimes(2);
@@ -322,6 +324,7 @@ describe('Selectors', () => {
       selector(firstState);
       selector(firstState);
       selector(secondState);
+      selector(secondState);
 
       expect(incrementOne).toHaveBeenCalledTimes(2);
       expect(incrementTwo).toHaveBeenCalledTimes(2);
@@ -433,6 +436,7 @@ describe('Selectors', () => {
       selector(firstState, props);
       selector(firstState, props);
       selector(secondState, props);
+      selector(secondState, props);
 
       expect(counter).toBe(2);
       expect(projectFn).toHaveBeenCalledTimes(2);

modules/store/src/selector.ts

@@ -70,13 +70,14 @@ export function defaultMemoize(
       return lastResult;
     }
 
+    lastArguments = arguments;
+
     const newResult = projectionFn.apply(null, arguments);
     if (isResultEqual(lastResult, newResult)) {
       return lastResult;
     }
 
     lastResult = newResult;
-    lastArguments = arguments;
 
     return newResult;
   }