From 4d4427dc5cc204d8ed2882239c83dc2c649718f5 Mon Sep 17 00:00:00 2001
From: kata <kata.choi@gmail.com>
Date: Thu, 12 Sep 2019 12:03:53 +0800
Subject: [PATCH] Improve selector caching for receipt data

---
 src/containers/NahmiiHoc/selectors.js          | 14 +++++---------
 .../NahmiiHoc/tests/selectors.test.js          | 18 +++++++++---------
 2 files changed, 14 insertions(+), 18 deletions(-)

diff --git a/src/containers/NahmiiHoc/selectors.js b/src/containers/NahmiiHoc/selectors.js
index 64951a0f..a66a62c1 100644
--- a/src/containers/NahmiiHoc/selectors.js
+++ b/src/containers/NahmiiHoc/selectors.js
@@ -23,17 +23,13 @@ export const createReceiptsSelector = createSelectorCreator(
   (previousArray, currentArray) => {
     let changed = false;
     currentArray.keySeq().forEach((address) => {
-      const previousReceipts = previousArray.getIn([address, 'receipts']);
-      const currentReceipts = currentArray.getIn([address, 'receipts']);
+      const previousReceipts = previousArray.getIn([address, 'receipts']) || fromJS([]);
+      const currentReceipts = currentArray.getIn([address, 'receipts']) || fromJS([]);
 
-      if (!currentReceipts && !previousReceipts) {
-        return;
-      }
+      const previousLastCreated = previousReceipts.getIn([previousReceipts.size - 1, 'created']);
+      const currentLastCreated = currentReceipts.getIn([currentReceipts.size - 1, 'created']);
 
-      if (
-        (!previousReceipts && currentReceipts) ||
-        (previousReceipts.size !== currentReceipts.size)
-      ) {
+      if (previousLastCreated !== currentLastCreated) {
         changed = true;
       }
     });
diff --git a/src/containers/NahmiiHoc/tests/selectors.test.js b/src/containers/NahmiiHoc/tests/selectors.test.js
index c3b70002..985dea6b 100644
--- a/src/containers/NahmiiHoc/tests/selectors.test.js
+++ b/src/containers/NahmiiHoc/tests/selectors.test.js
@@ -80,16 +80,11 @@ describe('makeSelectReceipts', () => {
         receiptsSelector(storeMock.setIn(['nahmiiHoc', 'receipts', address, 'receipts'], null))
       ).toEqual(receiptsLoaded.setIn([address, 'receipts'], null));
     });
-    it('should update the cache when the current receipts state has initialised array value', () => {
-      expect(
-        receiptsSelector(storeMock.setIn(['nahmiiHoc', 'receipts', address, 'receipts'], []))
-      ).toEqual(receiptsLoaded.setIn([address, 'receipts'], []));
-    });
   });
 
   describe('when previous receipts state has initialised', () => {
-    const store = storeMock.setIn(['nahmiiHoc', 'receipts', address, 'receipts'], fromJS([{}]));
-    const txs = receiptsLoaded.setIn([address, 'receipts'], fromJS([{}]));
+    const store = storeMock.setIn(['nahmiiHoc', 'receipts', address, 'receipts'], fromJS([{ created: '2018' }]));
+    const txs = receiptsLoaded.setIn([address, 'receipts'], fromJS([{ created: '2018' }]));
     beforeEach(() => {
       expect(
         receiptsSelector(store)
@@ -98,11 +93,16 @@ describe('makeSelectReceipts', () => {
     describe('should update the cache', () => {
       it('when the size of receipts array is different from previous state', () => {
         expect(receiptsSelector(
-          store.updateIn(['nahmiiHoc', 'receipts', address, 'receipts'], (arr) => arr.push({}))
-        )).toEqual(txs.updateIn([address, 'receipts'], (arr) => arr.push({})));
+          store.updateIn(['nahmiiHoc', 'receipts', address, 'receipts'], (arr) => arr.push(fromJS({ created: '2019' })))
+        )).toEqual(txs.updateIn([address, 'receipts'], (arr) => arr.push(fromJS({ created: '2019' }))));
       });
     });
     describe('should not update the cache', () => {
+      it('when the last created property is the same', () => {
+        expect(receiptsSelector(
+          store.updateIn(['nahmiiHoc', 'receipts', address, 'receipts'], (arr) => arr.push(fromJS({ created: '2018' })))
+        )).toEqual(txs);
+      });
       it('even when the loading state is changed', () => {
         expect(txs.getIn([address, 'loading'])).toEqual(false);
         expect(receiptsSelector(