refactor: stabilise actionHandler (#683)

apps/client/src/common/api/apiConstants.ts

@@ -13,6 +13,7 @@ export const RUNTIME = ['runtimeStore'];
 const location = window.location;
 const socketProtocol = location.protocol === 'https:' ? 'wss' : 'ws';
 export const isProduction = import.meta.env.MODE === 'production';
+export const isDev = !isProduction;
 
 const STATIC_PORT = 4001;
 export const serverPort = isProduction ? location.port : STATIC_PORT;

apps/client/src/common/hooks/useMemoisedFn.ts

@@ -0,0 +1,38 @@
+/**
+ * Shamelessly from https://ahooks.js.org/hooks/use-memoized-fn/
+ * Interesting technique discussed by Dan Abramov
+ * https://overreacted.io/making-setinterval-declarative-with-react-hooks/
+ */
+
+import { useMemo, useRef } from 'react';
+
+import { isDev } from '../api/apiConstants';
+
+type noop = (this: any, ...args: any[]) => any;
+
+type PickFunction<T extends noop> = (this: ThisParameterType<T>, ...args: Parameters<T>) => ReturnType<T>;
+
+export const isFunction = (value: unknown): value is (...args: any) => any => typeof value === 'function';
+
+export default function useMemoisedFn<T extends noop>(fn: T) {
+  if (isDev) {
+    if (!isFunction(fn)) {
+      console.error(`useMemoisedFn expected function as parameter, got ${typeof fn}`);
+    }
+  }
+
+  const fnRef = useRef<T>(fn);
+
+  // why not write `fnRef.current = fn`?
+  // https://github.com/alibaba/hooks/issues/728
+  fnRef.current = useMemo(() => fn, [fn]);
+
+  const memoizedFn = useRef<PickFunction<T>>();
+  if (!memoizedFn.current) {
+    memoizedFn.current = function (this, ...args) {
+      return fnRef.current.apply(this, args);
+    };
+  }
+
+  return memoizedFn.current as T;
+}

apps/client/src/features/rundown/RundownEntry.tsx

@@ -4,6 +4,7 @@ import { calculateDuration, getCueCandidate } from 'ontime-utils';
 
 import { RUNDOWN } from '../../common/api/apiConstants';
 import { useEventAction } from '../../common/hooks/useEventAction';
+import useMemoisedFn from '../../common/hooks/useMemoisedFn';
 import { ontimeQueryClient } from '../../common/queryClient';
 import { useAppMode } from '../../common/stores/appModeStore';
 import { useEditorSettings } from '../../common/stores/editorSettings';
@@ -61,10 +62,7 @@ export default function RundownEntry(props: RundownEntryProps) {
     value: unknown;
   };
 
-  // we assume the data is not changing in the lifecycle of this component
+  const actionHandler = useMemoisedFn((action: EventItemActions, payload?: number | FieldValue) => {
-  // changes to the data would make rundown re-render, also re-rendering this component
-  const actionHandler = useCallback(
-    (action: EventItemActions, payload?: number | FieldValue) => {
     switch (action) {
       case 'event': {
         const newEvent = { type: SupportedEvent.Event };
@@ -100,7 +98,7 @@ export default function RundownEntry(props: RundownEntryProps) {
       }
       case 'clone': {
         const newEvent = cloneEvent(data as OntimeEvent, data.id);
-          const rundown = ontimeQueryClient.getQueryData<GetRundownCached>(RUNDOWN)?.rundown ?? []
+        const rundown = ontimeQueryClient.getQueryData<GetRundownCached>(RUNDOWN)?.rundown ?? [];
         newEvent.cue = getCueCandidate(rundown, data.id);
         addEvent(newEvent);
         break;
@@ -135,21 +133,7 @@ export default function RundownEntry(props: RundownEntryProps) {
       default:
         throw new Error(`Unhandled event ${action}`);
     }
-    },
+  });
-    [
-      addEvent,
-      data,
-      defaultPublic,
-      deleteEvent,
-      emitError,
-      openId,
-      previousEventId,
-      removeOpenEvent,
-      startTimeIsLastEnd,
-      updateEvent,
-      swapEvents,
-    ],
-  );
 
   if (data.type === SupportedEvent.Event) {
     return (