Use useMemo and useCallback to memoize context values

assets/js/src/context/getFeaturesContext.jsx

@@ -1,5 +0,0 @@
-export default function getFeaturesContext(data) {
-  const flags = data.mailpoet_feature_flags;
-  const isSupported = (feature) => flags[feature] || false;
-  return { isSupported };
-}

assets/js/src/context/getSegmentsContext.jsx

@@ -1,5 +0,0 @@
-export default function getSegmentsContext(data) {
-  return {
-    all: data.mailpoetSegments,
-  };
-}

assets/js/src/context/getUsersContext.jsx

@@ -1,5 +0,0 @@
-export default function getUsersContext(data) {
-  return {
-    isNewUser: data.mailpoet_is_new_user,
-  };
-}

assets/js/src/context/index.jsx

@@ -1,7 +1,7 @@
 import React from 'react';
-import getFeaturesContext from './getFeaturesContext.jsx';
+import useFeaturesContext from './useFeaturesContext.jsx';
-import getSegmentsContext from './getSegmentsContext.jsx';
+import useSegmentsContext from './useSegmentsContext.jsx';
-import getUsersContext from './getUsersContext.jsx';
+import useUsersContext from './useUsersContext.jsx';
 import useNotices from './useNotices.jsx';
 
 /**
@@ -10,9 +10,9 @@ import useNotices from './useNotices.jsx';
  * some React hooks to build some parts of the context.
  */
 export function useGlobalContextValue(data) {
-  const features = getFeaturesContext(data);
+  const features = useFeaturesContext(data);
-  const segments = getSegmentsContext(data);
+  const segments = useSegmentsContext(data);
-  const users = getUsersContext(data);
+  const users = useUsersContext(data);
   const notices = useNotices();
   return {
     features, segments, users, notices,

assets/js/src/context/useFeaturesContext.jsx

@@ -0,0 +1,9 @@
+import React from 'react';
+
+export default function useFeaturesContext(data) {
+  return React.useMemo(() => {
+    const flags = data.mailpoet_feature_flags;
+    const isSupported = (feature) => flags[feature] || false;
+    return { isSupported };
+  }, [data]);
+}

assets/js/src/context/useNotices.jsx

@@ -4,23 +4,35 @@ export default () => {
   const [items, setItems] = React.useState([]);
   const [nextId, setNextId] = React.useState(1);
 
-  const getNextId = () => {
+  const getNextId = React.useCallback(() => {
     setNextId((x) => x + 1);
     return nextId;
-  };
+  }, [nextId]);
 
-  const add = (item) => {
+  const add = React.useCallback((item) => {
     setItems((xs) => [...xs, { ...item, id: item.id || getNextId() }]);
-  };
+  }, [getNextId]);
 
-  const remove = (id) => {
+  const remove = React.useCallback((id) => {
     setItems((xs) => xs.filter((x) => x.id !== id));
-  };
+  }, []);
 
-  const success = (content, props = {}) => add({ ...props, type: 'success', children: content });
+  const success = React.useCallback(
-  const info = (content, props = {}) => add({ ...props, type: 'info', children: content });
+    (content, props = {}) => add({ ...props, type: 'success', children: content }),
-  const warning = (content, props = {}) => add({ ...props, type: 'warning', children: content });
+    [add]
-  const error = (content, props = {}) => add({ ...props, type: 'error', children: content });
+  );
+  const info = React.useCallback(
+    (content, props = {}) => add({ ...props, type: 'info', children: content }),
+    [add]
+  );
+  const warning = React.useCallback(
+    (content, props = {}) => add({ ...props, type: 'warning', children: content }),
+    [add]
+  );
+  const error = React.useCallback(
+    (content, props = {}) => add({ ...props, type: 'error', children: content }),
+    [add]
+  );
 
   return {
     items, success, info, warning, error, remove,

assets/js/src/context/useSegmentsContext.jsx

@@ -0,0 +1,7 @@
+import React from 'react';
+
+export default function useSegmentsContext(data) {
+  return React.useMemo(() => ({
+    all: data.mailpoetSegments,
+  }), [data]);
+}

assets/js/src/context/useUsersContext.jsx

@@ -0,0 +1,7 @@
+import React from 'react';
+
+export default function useUsersContext(data) {
+  return React.useMemo(() => ({
+    isNewUser: data.mailpoet_is_new_user,
+  }), [data]);
+}

assets/js/src/experimental_features/experimental_features.jsx

@@ -7,10 +7,9 @@ import Notices from 'notices/notices.jsx';
 const ExperimentalFeatures = () => {
   const [flags, setFlags] = useState(null);
   const contextValue = useGlobalContextValue(window);
-  const [mounted, setMounted] = useState(false);
+  const showError = contextValue.notices.error;
 
   useEffect(() => {
-    if (!mounted) {
     MailPoet.Ajax.post({
       api_version: window.mailpoet_api_version,
       endpoint: 'featureFlags',
@@ -20,15 +19,13 @@ const ExperimentalFeatures = () => {
       setFlags(flagsMap);
     }).fail((response) => {
       if (response.errors.length > 0) {
-          contextValue.notices.error(
+        showError(
           <>{response.errors.map((error) => <p>{error.message}</p>)}</>,
           { scroll: true }
         );
       }
     });
-      setMounted(true);
+  }, [showError]);
-    }
-  }, [contextValue.notices, mounted]);
 
   function handleChange(event) {
     const name = event.target.name;
@@ -49,7 +46,7 @@ const ExperimentalFeatures = () => {
       contextValue.notices.success(<p>{message}</p>);
     }).fail((response) => {
       if (response.errors.length > 0) {
-        contextValue.notices.error(
+        showError(
           response.errors.map((error) => <p key={error.message}>{error.message}</p>),
           { scroll: true }
         );