Ensures extra calculations only run for react-native for web.

Author: alexkendall

src/WheelPicker.tsx

@@ -10,6 +10,7 @@ import {
   ViewProps,
   FlatListProps,
   FlatList,
+  Platform
 } from 'react-native';
 import styles from './WheelPicker.styles';
 import WheelPickerItem from './WheelPickerItem';
@@ -51,7 +52,6 @@ const WheelPicker: React.FC<Props> = ({
   const [scrollY] = useState(new Animated.Value(0));
   const flatList = useRef<any>(null)
 
-  const SCROLL_DID_STOP_TIMEOUT = 500
   const lastScrollTimestamp = useRef(new Date().getTime())
 
   const containerHeight = (1 + visibleRest * 2) * itemHeight;
@@ -101,21 +101,27 @@ const WheelPicker: React.FC<Props> = ({
 
 
   useEffect(() => {
-    const intervalID = setInterval(() => {
-      const time = new Date().getTime()
-      const difference = time - lastScrollTimestamp.current
-      if (difference > SCROLL_DID_STOP_TIMEOUT) {
-        flatList.current?.scrollToIndex({ index: scrollIndex, animated: true })
+    if (Platform.OS === "web") {
+      const SCROLL_COOLDOWN_MILISECONDS = 100
+      const SCROLL_DID_STOP_TIMEOUT = 500
+      const intervalID = setInterval(() => {
+        const time = new Date().getTime()
+        const difference = time - lastScrollTimestamp.current
+        if (difference > SCROLL_DID_STOP_TIMEOUT) {
+          flatList.current?.scrollToIndex({ index: scrollIndex, animated: true })
+        }
+      }, SCROLL_COOLDOWN_MILISECONDS)
+      return () => {
+        clearInterval(intervalID)
       }
-    }, 100)
-    return () => {
-      clearInterval(intervalID)
     }
   }, [scrollIndex])
 
   useEffect(() => {
-    if (onChange) {
-      onChange(scrollIndex)
+    if (Platform.OS === "web") {
+      if (onChange) {
+        onChange(scrollIndex)
+      }
     }
   }, [scrollIndex])
 
@@ -127,10 +133,12 @@ const WheelPicker: React.FC<Props> = ({
       layoutMeasurement: { height: number, width: number },
     }
   }) => {
-    const positionY = event?.nativeEvent?.contentOffset?.y ?? 0;
-    const index = Math.round(positionY / itemHeight)
-    setScrollIndex(index)
-    lastScrollTimestamp.current = new Date().getTime()
+    if (Platform.OS === "web") {
+      const positionY = event?.nativeEvent?.contentOffset?.y ?? 0;
+      const index = Math.round(positionY / itemHeight)
+      setScrollIndex(index)
+      lastScrollTimestamp.current = new Date().getTime()
+    }
   }
 
   return (