Add cache for working moments (#1048)

# What this PR does

## Which issue(s) this PR fixes

Add cache to avoid heavy calculations to render working hours shades

## Checklist

- [ ] Tests updated
- [ ] Documentation added
- [ ] `CHANGELOG.md` updated

grafana-plugin/package.json

@@ -116,6 +116,7 @@
     "eslint-plugin-import": "^2.25.4",
     "mobx": "5.13.0",
     "mobx-react": "6.1.1",
+    "object-hash": "^3.0.0",
     "prettier": "^2.8.2",
     "rc-table": "^7.17.1",
     "react-copy-to-clipboard": "^5.0.2",

grafana-plugin/src/components/WorkingHours/WorkingHours.helpers.ts

@@ -1,8 +1,21 @@
 import dayjs from 'dayjs';
+import hash from 'object-hash';
+
+const workingMomentsCache = {};
+
+const getKey = (startMoment, endMoment, workingHours, timezone) => {
+  return `${startMoment}-${endMoment}-${hash(workingHours)}-${timezone}`;
+};
 
 export const getWorkingMoments = (startMoment, endMoment, workingHours, timezone) => {
   const weekdays = dayjs.weekdays();
 
+  const key = getKey(startMoment, endMoment, workingHours, timezone);
+
+  if (workingMomentsCache[key]) {
+    return workingMomentsCache[key];
+  }
+
   const momentToStartIteration = dayjs().tz(timezone).utcOffset() === 0 ? startMoment : startMoment.tz(timezone);
 
   const dayOfWeekToStartIteration = momentToStartIteration.format('dddd');
@@ -64,14 +77,16 @@ export const getWorkingMoments = (startMoment, endMoment, workingHours, timezone
     }
   }
 
+  workingMomentsCache[key] = workingMoments;
+
   return workingMoments;
 };
 
-export const getNonWorkingMoments = (startMoment, endMoment, workingHours) => {
+export const getNonWorkingMoments = (startMoment, endMoment, workingMoments) => {
   const nonWorkingMoments = [{ start: startMoment, end: endMoment }];
 
   let lastNonWorkingRange = nonWorkingMoments[0];
-  for (const [_i, range] of workingHours.entries()) {
+  for (const [_i, range] of workingMoments.entries()) {
     lastNonWorkingRange.end = range.start;
 
     lastNonWorkingRange = { start: range.end, end: undefined };

grafana-plugin/yarn.lock

@@ -9802,6 +9802,11 @@ object-copy@^0.1.0:
     define-property "^0.2.5"
     kind-of "^3.0.3"
 
+object-hash@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/object-hash/-/object-hash-3.0.0.tgz#73f97f753e7baffc0e2cc9d6e079079744ac82e9"
+  integrity sha512-RSn9F68PjH9HqtltsSnqYC1XXoWe9Bju5+213R98cNGttag9q9yAOTzdbsqvIa7aNm5WffBZFpWYr2aWrklWAw==
+
 object-inspect@^1.12.2, object-inspect@^1.9.0:
   version "1.12.2"
   resolved "https://registry.yarnpkg.com/object-inspect/-/object-inspect-1.12.2.tgz#c0641f26394532f28ab8d796ab954e43c009a8ea"