react-native-reanimated#onChange TypeScript Examples

PaperOnboardingComponent = forwardRef<
  PaperOnboarding,
  PaperOnboardingProps
>(
  (
    {
      data,
      safeInsets: _safeInsets,
      direction = DEFAULT_DIRECTION,
      // indicator config
      indicatorSize = DEFAULT_INDICATOR_SIZE,
      indicatorBackgroundColor = DEFAULT_INDICATOR_BACKGROUND_COLOR,
      indicatorBorderColor = DEFAULT_INDICATOR_BORDER_COLOR,
      // override styles
      titleStyle,
      descriptionStyle,
      // close button config
      closeButton,
      closeButtonTextStyle,
      closeButtonText = DEFAULT_CLOSE_BUTTON_TEXT,
      onCloseButtonPress = DEFAULT_CLOSE_BUTTON_CALLBACK,
      onIndexChange,
    },
    ref
  ) => {
    // state
    const [dimensions, setDimensions] =
      useState<PaperOnboardingScreenDimensions>({
        width: Dimensions.get('window').width,
        height: Dimensions.get('window').height,
      });

    // refs
    const indexRef = useRef<number>(0);
    const pagesRef = useRef<Array<Animated.View | null>>(data.map(() => null));

    //#region variables
    const safeInsets = useMemo<Required<Insets>>(() => {
      return {
        top: _safeInsets?.top ?? DEFAULT_SAFE_INSET,
        bottom: _safeInsets?.bottom ?? DEFAULT_SAFE_INSET,
        left: _safeInsets?.left ?? DEFAULT_SAFE_INSET,
        right: _safeInsets?.right ?? DEFAULT_SAFE_INSET,
      };
    }, [_safeInsets]);
    const indicatorsContainerLeftPadding = useMemo(() => {
      const containerLeftPadding = dimensions.width / 2 - indicatorSize / 2;
      return I18nManager.isRTL
        ? -containerLeftPadding + indicatorSize * (data.length - 1)
        : containerLeftPadding;
    }, [dimensions.width, indicatorSize, data.length]);
    //#endregion

    //#region animated variables
    const { gestureHandler, state, translation, velocity } =
      usePanGestureHandler();
    const animatedStaticIndex = useValue<number>(0);
    const animatedOverrideIndex = useValue<number>(0);
    const animatedIndex = useTiming({
      animatedStaticIndex,
      animatedOverrideIndex,
      value: direction === 'horizontal' ? translation.x : translation.y,
      velocity: direction === 'horizontal' ? velocity.x : velocity.y,
      state: state,
      size: data.length,
      screenWidth: dimensions.width,
    });
    const indicatorsContainerPosition = useMemo(
      () => data.map((_, index) => index * indicatorSize * -1),
      [data, indicatorSize]
    );
    const animatedIndicatorsContainerPosition = useMemo(
      () =>
        add(
          interpolate(animatedIndex, {
            inputRange: data.map((_, index) => index),
            outputRange: I18nManager.isRTL
              ? indicatorsContainerPosition.reverse()
              : indicatorsContainerPosition,
            extrapolate: Animated.Extrapolate.CLAMP,
          }),
          indicatorsContainerLeftPadding
        ),
      [
        data,
        animatedIndex,
        indicatorsContainerLeftPadding,
        indicatorsContainerPosition,
      ]
    );
    //#endregion

    //#region callbacks
    const handlePageRef = useCallback((pageRef, index) => {
      pagesRef.current[index] = pageRef;
    }, []);

    const handleOnLayout = useCallback(
      ({
        nativeEvent: {
          layout: { width, height },
        },
      }: LayoutChangeEvent) => {
        setDimensions({
          width,
          height,
        });
      },
      []
    );
    //#endregion

    //#region public methods
    const handleNavigateToNextPage = useCallback(() => {
      const currentIndex = indexRef.current;
      if (currentIndex === data.length - 1) {
        return;
      }
      animatedOverrideIndex.setValue(currentIndex + 1);
    }, [data, animatedOverrideIndex]);
    const handleNavigateToPreviousPage = useCallback(() => {
      const currentIndex = indexRef.current;
      if (currentIndex === 0) {
        return;
      }
      animatedOverrideIndex.setValue(currentIndex - 1);
    }, [animatedOverrideIndex]);
    useImperativeHandle(
      ref,
      () => ({
        next: handleNavigateToNextPage,
        previous: handleNavigateToPreviousPage,
      }),
      [handleNavigateToNextPage, handleNavigateToPreviousPage]
    );
    //#endregion

    //#region effects
    useCode(
      () =>
        onChange(
          animatedStaticIndex,
          call([animatedStaticIndex], args => {
            indexRef.current = args[0];
            /**
             * @DEV
             * here we directly manipulate pages native props by setting `pointerEvents`
             * to `auto` for current page and `none` for others.
             */
            pagesRef.current.map((pageRef, _index) => {
              // @ts-ignore
              pageRef.setNativeProps({
                pointerEvents: _index === args[0] ? 'auto' : 'none',
              });
            });

            if (onIndexChange) {
              onIndexChange(args[0]);
            }
          })
        ),
      []
    );
    //#endregion

    // renders
    return (
      <PanGestureHandler {...gestureHandler}>
        <Animated.View onLayout={handleOnLayout} style={styles.container}>
          <Background
            animatedIndex={animatedIndex}
            data={data}
            safeInsets={safeInsets}
            screenDimensions={dimensions}
            indicatorSize={indicatorSize}
            animatedIndicatorsContainerPosition={
              animatedIndicatorsContainerPosition
            }
          />

          {data.map((item, index) => (
            <Page
              key={`page-${index}`}
              index={index}
              item={item}
              animatedIndex={animatedIndex}
              indicatorSize={indicatorSize}
              titleStyle={titleStyle}
              descriptionStyle={descriptionStyle}
              safeInsets={safeInsets}
              screenDimensions={dimensions}
              handleRef={handlePageRef}
            />
          ))}

          <IndicatorsContainer
            data={data}
            animatedIndex={animatedIndex}
            animatedIndicatorsContainerPosition={
              animatedIndicatorsContainerPosition
            }
            indicatorSize={indicatorSize}
            indicatorBackgroundColor={indicatorBackgroundColor}
            indicatorBorderColor={indicatorBorderColor}
            safeInsets={safeInsets}
          />

          <CloseButton
            data={data}
            animatedIndex={animatedIndex}
            safeInsets={safeInsets}
            closeButtonText={closeButtonText}
            closeButtonTextStyle={closeButtonTextStyle}
            closeButton={closeButton}
            onCloseButtonPress={onCloseButtonPress}
          />
        </Animated.View>
      </PanGestureHandler>
    );
  }
)

useTiming = ({
  animatedStaticIndex,
  animatedOverrideIndex,
  value,
  velocity,
  state,
  size,
  screenWidth,
}: useTimingProps) => {
  const clock = useClock();
  const isManuallyAnimated = useValue(0);

  const config = useMemo(
    () => ({
      toValue: new Animated.Value(0),
      duration: 500,
      easing: Easing.out(Easing.exp),
    }),
    []
  );

  const animationState = useMemo(
    () => ({
      finished: new Animated.Value(0),
      position: new Animated.Value(0),
      frameTime: new Animated.Value(0),
      time: new Animated.Value(0),
    }),
    []
  );

  const valueClamp = useMemo(
    () =>
      interpolate(value, {
        inputRange: [screenWidth * -1, 0, screenWidth],
        outputRange: I18nManager.isRTL ? [-1, 0, 1] : [1, 0, -1],
        extrapolate: Animated.Extrapolate.CLAMP,
      }),
    [value, screenWidth]
  );

  const velocityClamp = useMemo(
    () =>
      interpolate(velocity, {
        inputRange: [screenWidth * -2, 0, screenWidth * 2],
        outputRange: I18nManager.isRTL ? [-0.5, 0, 0.5] : [0.5, 0, -0.5],
        extrapolate: Animated.Extrapolate.CLAMP,
      }),
    [screenWidth, velocity]
  );

  const isTimingInterrupted = and(eq(state, State.BEGAN), clockRunning(clock));
  const finishTiming = useMemo(
    () => [
      set(animatedStaticIndex, config.toValue),
      set(animatedOverrideIndex, config.toValue),
      set(animationState.frameTime, 0),
      set(animationState.time, 0),
      set(state, State.UNDETERMINED),
      set(isManuallyAnimated, 0),
      stopClock(clock),
    ],
    [
      state,
      animatedOverrideIndex,
      animatedStaticIndex,
      animationState.frameTime,
      animationState.time,
      clock,
      config.toValue,
      isManuallyAnimated,
    ]
  );

  const shouldAnimate = useMemo(
    () =>
      and(
        not(and(eq(animatedStaticIndex, 0), lessThan(valueClamp, 0))),
        not(and(eq(animatedStaticIndex, size - 1), greaterThan(valueClamp, 0)))
      ),
    [animatedStaticIndex, size, valueClamp]
  );
  const shouldReset = useMemo(
    () => not(greaterThan(add(abs(valueClamp), abs(velocityClamp)), 0.5)),
    [valueClamp, velocityClamp]
  );
  const shouldAnimateNext = useMemo(
    () =>
      greaterThan(
        add(animationState.position, velocityClamp),
        animatedStaticIndex
      ),
    [animatedStaticIndex, animationState.position, velocityClamp]
  );

  const animatedPosition = useMemo(
    () =>
      block([
        cond(isTimingInterrupted, finishTiming),
        cond(
          eq(state, State.ACTIVE),
          cond(
            and(
              not(and(eq(animatedStaticIndex, 0), lessThan(valueClamp, 0))),
              not(
                and(
                  eq(animatedStaticIndex, size - 1),
                  greaterThan(valueClamp, 0)
                )
              )
            ),
            [
              set(animationState.finished, 0),
              set(
                animationState.position,
                add(animatedStaticIndex, valueClamp)
              ),
            ]
          )
        ),

        onChange(animatedOverrideIndex, [
          set(isManuallyAnimated, 1),
          set(animationState.finished, 0),
        ]),

        cond(or(eq(state, State.END), isManuallyAnimated), [
          cond(and(not(clockRunning(clock)), not(animationState.finished)), [
            cond(
              isManuallyAnimated,
              set(config.toValue, animatedOverrideIndex),
              cond(
                or(shouldReset, not(shouldAnimate)),
                set(config.toValue, animatedStaticIndex),
                cond(
                  shouldAnimateNext,
                  set(config.toValue, add(animatedStaticIndex, 1)),
                  set(config.toValue, sub(animatedStaticIndex, 1))
                )
              )
            ),
            set(animationState.finished, 0),
            set(animationState.frameTime, 0),
            set(animationState.time, 0),
            startClock(clock),
          ]),
          timing(clock, animationState, config),
          cond(animationState.finished, finishTiming),
        ]),

        animationState.position,
      ]),
    [
      size,
      state,
      animatedOverrideIndex,
      animatedStaticIndex,
      animationState,
      clock,
      config,
      finishTiming,
      isManuallyAnimated,
      isTimingInterrupted,
      shouldAnimate,
      shouldAnimateNext,
      shouldReset,
      valueClamp,
    ]
  );
  return animatedPosition;
}

StickyItemFlatList = forwardRef(
  <T extends {}>(props: StickyItemFlatListProps<T>, ref: Ref<FlatList<T>>) => {
    const {
      initialScrollIndex = 0,
      decelerationRate = DEFAULT_DECELERATION_RATE,
      itemWidth,
      itemHeight,
      separatorSize = DEFAULT_SEPARATOR_SIZE,
      borderRadius = DEFAULT_BORDER_RADIUS,
      stickyItemActiveOpacity = DEFAULT_STICKY_ITEM_ACTIVE_OPACITY,
      stickyItemWidth,
      stickyItemHeight,
      stickyItemBackgroundColors,
      stickyItemContent,
      onStickyItemPress,
      isRTL = DEFAULT_IS_RTL,
      ItemSeparatorComponent = Separator,
      ...rest
    } = props;

    // refs
    const flatListRef = useRef<FlatList<T>>(null);
    const tapRef = useRef<TapGestureHandler>(null);

    //#region variables
    const itemWidthWithSeparator = useMemo(
      () => itemWidth + separatorSize,
      [itemWidth, separatorSize]
    );
    const separatorProps = useMemo(
      () => ({
        size: separatorSize,
      }),
      [separatorSize]
    );
    //#endregion

    //#region styles
    const contentContainerStyle = useMemo(
      () => [
        rest.contentContainerStyle,
        {
          paddingLeft: itemWidth + separatorSize * 2,
          paddingRight: separatorSize,
        },
      ],
      [rest.contentContainerStyle, itemWidth, separatorSize]
    );
    //#endregion

    //#region methods
    const getHitSlop = useCallback(
      isMinimized => {
        const verticalPosition = isMinimized
          ? -((itemHeight - stickyItemHeight) / 2)
          : 0;
        const startPosition = isMinimized ? 0 : -separatorSize;
        const endPosition = isMinimized
          ? -(SCREEN_WIDTH - stickyItemWidth)
          : -(SCREEN_WIDTH - separatorSize - itemWidth);

        return {
          top: verticalPosition,
          right: isRTL ? startPosition : endPosition,
          left: isRTL ? endPosition : startPosition,
          bottom: verticalPosition,
        };
      },
      [
        itemWidth,
        itemHeight,
        stickyItemWidth,
        stickyItemHeight,
        separatorSize,
        isRTL,
      ]
    );
    const getItemLayout = useCallback(
      (_, index) => {
        return {
          length: itemWidthWithSeparator,
          // sticky item + previous items width
          offset: itemWidthWithSeparator + itemWidthWithSeparator * index,
          index,
        };
      },
      [itemWidthWithSeparator]
    );
    //#endregion

    //#region gesture
    const x = useValue(0);
    const tapState = useValue(State.UNDETERMINED);
    const tapGestures = useGestureHandler({ state: tapState });
    const onScroll = event([
      {
        nativeEvent: {
          contentOffset: {
            x,
          },
        },
      },
    ]);
    const onScrollEnd = event([
      {
        nativeEvent: {
          contentOffset: {
            x,
          },
        },
      },
    ]);
    //#endregion

    //#region effects
    //@ts-ignore
    useImperativeHandle(ref, () => flatListRef.current!.getNode());
    useCode(
      () =>
        cond(eq(tapState, State.END), [
          call([tapState], () => {
            if (onStickyItemPress) {
              onStickyItemPress();
            }
          }),
          set(tapState, State.UNDETERMINED),
        ]),
      [tapState]
    );
    useCode(
      () =>
        onChange(
          x,
          call([x], args => {
            if (tapRef.current) {
              const isMinimized = args[0] > 0;
              // @ts-ignore
              tapRef.current.setNativeProps({
                hitSlop: getHitSlop(isMinimized),
              });
            }
          })
        ),
      [
        x,
        itemWidth,
        itemHeight,
        stickyItemWidth,
        stickyItemWidth,
        separatorSize,
      ]
    );
    useEffect(() => {
      /**
       * @DEV
       * to fix stick item position with fast refresh
       */
      x.setValue(0);

      if (tapRef.current) {
        // @ts-ignore
        tapRef.current.setNativeProps({
          hitSlop: getHitSlop(initialScrollIndex !== 0),
        });
      }
      // eslint-disable-next-line react-hooks/exhaustive-deps
    }, [getHitSlop]);
    //#endregion

    // render
    const renderSeparator = useCallback(() => {
      if (typeof ItemSeparatorComponent === 'function') {
        // @ts-ignore
        return ItemSeparatorComponent(separatorProps);
      } else {
        // @ts-ignore
        return <ItemSeparatorComponent size={separatorProps.size} />;
      }
    }, [ItemSeparatorComponent, separatorProps]);

    return (
      <TapGestureHandler
        ref={tapRef}
        waitFor={flatListRef}
        shouldCancelWhenOutside={true}
        {...tapGestures}
      >
        <Animated.View>
          <AnimatedFlatList
            {...rest}
            ref={flatListRef}
            initialScrollIndex={initialScrollIndex}
            inverted={isRTL}
            ItemSeparatorComponent={renderSeparator}
            contentContainerStyle={contentContainerStyle}
            horizontal={true}
            showsHorizontalScrollIndicator={false}
            scrollEventThrottle={1}
            pagingEnabled={true}
            decelerationRate={decelerationRate}
            snapToAlignment={'start'}
            snapToInterval={itemWidth + separatorSize}
            onScroll={onScroll}
            onScrollAnimationEnd={onScrollEnd}
            getItemLayout={getItemLayout}
          />
          <StickyItem
            x={x}
            tapState={tapState}
            itemWidth={itemWidth}
            itemHeight={itemHeight}
            separatorSize={separatorSize}
            borderRadius={borderRadius}
            stickyItemActiveOpacity={stickyItemActiveOpacity}
            stickyItemWidth={stickyItemWidth}
            stickyItemHeight={stickyItemHeight}
            stickyItemBackgroundColors={stickyItemBackgroundColors}
            stickyItemContent={stickyItemContent}
            isRTL={isRTL}
          />
        </Animated.View>
      </TapGestureHandler>
    );
  }
)

render() {
    const {
      renderHandle,
      snapPoints,
      initialSnapIndex,
      componentType,
      onSettle,
      animatedPosition,
      containerStyle,
      ...rest
    } = this.props;
    const AnimatedScrollableComponent = this.scrollComponent;
    const normalisedSnapPoints = this.getNormalisedSnapPoints();
    const initialSnap = normalisedSnapPoints[initialSnapIndex];

    const Content = (
      <Animated.View
        style={[
          StyleSheet.absoluteFillObject,
          containerStyle,
          // @ts-ignore
          {
            transform: [{ translateY: this.translateY }],
          },
        ]}
      >
        <PanGestureHandler
          ref={this.drawerHandleRef}
          shouldCancelWhenOutside={false}
          simultaneousHandlers={this.masterDrawer}
          onGestureEvent={this.onHandleGestureEvent}
          onHandlerStateChange={this.onHandleGestureEvent}
        >
          <Animated.View>{renderHandle()}</Animated.View>
        </PanGestureHandler>
        <PanGestureHandler
          ref={this.drawerContentRef}
          simultaneousHandlers={[this.scrollComponentRef, this.masterDrawer]}
          shouldCancelWhenOutside={false}
          onGestureEvent={this.onDrawerGestureEvent}
          onHandlerStateChange={this.onDrawerGestureEvent}
        >
          <Animated.View style={styles.container}>
            <NativeViewGestureHandler
              ref={this.scrollComponentRef}
              waitFor={this.masterDrawer}
              simultaneousHandlers={this.drawerContentRef}
            >
              <AnimatedScrollableComponent
                overScrollMode="never"
                bounces={false}
                {...rest}
                ref={this.props.innerRef}
                // @ts-ignore
                decelerationRate={this.decelerationRate}
                onScrollBeginDrag={this.onScrollBeginDrag}
                scrollEventThrottle={1}
                contentContainerStyle={[
                  rest.contentContainerStyle,
                  { paddingBottom: this.getNormalisedSnapPoints()[0] },
                ]}
              />
            </NativeViewGestureHandler>
          </Animated.View>
        </PanGestureHandler>
        {this.props.animatedPosition && (
          <Animated.Code
            exec={onChange(
              this.position,
              set(this.props.animatedPosition, this.position)
            )}
          />
        )}
        <Animated.Code
          exec={onChange(
            this.dragY,
            cond(not(eq(this.dragY, 0)), set(this.prevDragY, this.dragY))
          )}
        />
        <Animated.Code
          exec={onChange(
            this.didGestureFinish,
            cond(this.didGestureFinish, [
              this.didScrollUpAndPullDown,
              this.setTranslationY,
              set(
                this.tempDestSnapPoint,
                add(normalisedSnapPoints[0], this.extraOffset)
              ),
              set(this.nextSnapIndex, 0),
              set(this.destSnapPoint, this.calculateNextSnapPoint()),
              cond(
                and(
                  greaterThan(this.dragY, this.lastStartScrollY),
                  this.isAndroid,
                  not(this.dragWithHandle)
                ),
                call([], () => {
                  // This prevents the scroll glide from happening on Android when pulling down with inertia.
                  // It's not perfect, but does the job for now
                  const { method, args } = imperativeScrollOptions[
                    this.props.componentType
                  ];
                  // @ts-ignore
                  const node = this.props.innerRef.current?.getNode();

                  if (
                    node &&
                    node[method] &&
                    ((this.props.componentType === 'FlatList' &&
                      (this.props?.data?.length || 0) > 0) ||
                      (this.props.componentType === 'SectionList' &&
                        this.props.sections.length > 0) ||
                      this.props.componentType === 'ScrollView')
                  ) {
                    node[method](args);
                  }
                })
              ),
              set(this.dragY, 0),
              set(this.velocityY, 0),
              set(
                this.lastSnap,
                sub(
                  this.destSnapPoint,
                  cond(
                    eq(this.scrollUpAndPullDown, 1),
                    this.lastStartScrollY,
                    0
                  )
                )
              ),
              call([this.lastSnap], ([value]) => {
                // This is the TapGHandler trick
                // @ts-ignore
                this.masterDrawer?.current?.setNativeProps({
                  maxDeltaY: value - this.getNormalisedSnapPoints()[0],
                });
              }),
              set(
                this.decelerationRate,
                cond(
                  eq(this.isAndroid, 1),
                  cond(
                    eq(this.lastSnap, normalisedSnapPoints[0]),
                    ANDROID_NORMAL_DECELERATION_RATE,
                    0
                  ),
                  IOS_NORMAL_DECELERATION_RATE
                )
              ),
            ])
          )}
        />
        <Animated.Code
          exec={onChange(this.isManuallySetValue, [
            cond(
              this.isManuallySetValue,
              [
                set(this.destSnapPoint, this.manualYOffset),
                set(this.animationFinished, 0),
                set(this.lastSnap, this.manualYOffset),
                call([this.lastSnap], ([value]) => {
                  // This is the TapGHandler trick
                  // @ts-ignore
                  this.masterDrawer?.current?.setNativeProps({
                    maxDeltaY: value - this.getNormalisedSnapPoints()[0],
                  });
                }),
              ],
              [set(this.nextSnapIndex, 0)]
            ),
          ])}
        />
      </Animated.View>
    );

    // On Android, having an intermediary view with pointerEvents="box-none", breaks the
    // waitFor logic
    if (Platform.OS === 'android') {
      return (
        <TapGestureHandler
          maxDurationMs={100000}
          ref={this.masterDrawer}
          maxDeltaY={initialSnap - this.getNormalisedSnapPoints()[0]}
          shouldCancelWhenOutside={false}
        >
          {Content}
        </TapGestureHandler>
      );
    }

    // On iOS, We need to wrap the content on a view with PointerEvents box-none
    // So that we can start scrolling automatically when reaching the top without
    // Stopping the gesture
    return (
      <TapGestureHandler
        maxDurationMs={100000}
        ref={this.masterDrawer}
        maxDeltaY={initialSnap - this.getNormalisedSnapPoints()[0]}
      >
        <View style={StyleSheet.absoluteFillObject} pointerEvents="box-none">
          {Content}
        </View>
      </TapGestureHandler>
    );
  }