fix(blur): Migrate web to a function component and fix reanimated err…

…ors (#27721)

# Why

- [`setNativeProps` was
removed](necolas/react-native-web@e68c327)
so we need to set the style props directly. This can be reproduced by
opening NCL and going to the blur route.
- Tested the change in both safari and chrome.
- This PR also drops support for older browsers in favor of the
unsupported style warning.

---------

Co-authored-by: Expo Bot <34669131+expo-bot@users.noreply.github.com>

packages/expo-blur/CHANGELOG.md

@@ -10,6 +10,8 @@
 
 ### 🐛 Bug fixes
 
+- Migrate web to a function component and fix reanimated errors related to [`setNativeProps` being removed](https://github.com/necolas/react-native-web/commit/e68c32770757194af103cca0095c0c204995505b). ([#27721](https://github.com/expo/expo/pull/27721) by [@EvanBacon](https://github.com/EvanBacon))
+
 ### 💡 Others
 
 ## 12.9.2 - 2024-02-16

packages/expo-blur/src/BlurView.web.tsx

@@ -1,65 +1,64 @@
 // Copyright © 2024 650 Industries.
-
 'use client';
-
-import * as React from 'react';
+import { forwardRef, useImperativeHandle, useRef } from 'react';
 import { View } from 'react-native';
 
 import { BlurViewProps } from './BlurView.types';
 import getBackgroundColor from './getBackgroundColor';
 
-// TODO: Class components are not supported with React Server Components.
-export default class BlurView extends React.Component<BlurViewProps> {
-  private blurViewRef = React.createRef<View>();
+const BlurView = forwardRef<{ setNativeProps: (props: BlurViewProps) => void }, BlurViewProps>(
+  ({ tint = 'default', intensity = 50, style, ...props }, ref) => {
+    const blurViewRef = useRef<HTMLDivElement>(null);
+    const blurStyle = getBlurStyle({ tint, intensity });
 
-  /**
-   * Reanimated will detect and call this function with animated styles passed as props on every
-   * animation frame. We want to extract intensity from the props, then create and apply new styles,
-   * which create the blur based on the intensity and current tint.
-   */
-  setNativeProps(nativeProps) {
-    const { style, tint, intensity: standardIntensity } = this.props;
-    const intensity = nativeProps.style.intensity ?? standardIntensity;
-    const blurStyle = getBlurStyle({ intensity, tint });
-    this.blurViewRef?.current?.setNativeProps({
-      ...nativeProps,
-      style: [style, blurStyle, nativeProps.style],
-    });
-  }
+    useImperativeHandle(
+      ref,
+      () => ({
+        setNativeProps: (nativeProps: BlurViewProps) => {
+          if (!blurViewRef.current?.style) {
+            return;
+          }
 
-  render() {
-    const { tint = 'default', intensity = 50, style, ...props } = this.props;
-    const blurStyle = getBlurStyle({ tint, intensity });
-    return <View {...props} style={[style, blurStyle]} ref={this.blurViewRef} />;
-  }
-}
+          // @ts-expect-error: `style.intensity` is not defined in the types
+          const nextIntensity = nativeProps.style?.intensity ?? intensity;
+          const blurStyle = getBlurStyle({ intensity: nextIntensity, tint: tint ?? 'default' });
+          if (nativeProps.style) {
+            for (const key in nativeProps.style) {
+              if (key !== 'intensity') {
+                blurViewRef.current.style[key] = nativeProps.style[key];
+              }
+            }
+          }
 
-function isBlurSupported(): boolean {
-  // TODO: Replace with CSS or static extraction to ensure hydration errors cannot happen.
-  // Enable by default in Node.js
-  if (typeof window === 'undefined') {
-    return true;
+          blurViewRef.current.style.backgroundColor = blurStyle.backgroundColor;
+          blurViewRef.current.style.backdropFilter = blurStyle.backdropFilter;
+          blurViewRef.current.style['webkitBackdropFilter'] = blurStyle.WebkitBackdropFilter;
+        },
+      }),
+      [intensity, tint]
+    );
+
+    return (
+      <View
+        {...props}
+        style={[style, blurStyle]}
+        /** @ts-expect-error: mismatch in ref type to support manually setting style props. */
+        ref={blurViewRef}
+      />
+    );
   }
-  // https://developer.mozilla.org/en-US/docs/Web/API/CSS/supports
-  // https://developer.mozilla.org/en-US/docs/Web/CSS/backdrop-filter#Browser_compatibility
-  return (
-    typeof CSS !== 'undefined' &&
-    (CSS.supports('-webkit-backdrop-filter', 'blur(1px)') ||
-      CSS.supports('backdrop-filter', 'blur(1px)'))
-  );
-}
+);
 
-function getBlurStyle({ intensity, tint }): Record<string, string> {
-  const style: Record<string, string> = {
+function getBlurStyle({
+  intensity,
+  tint,
+}: Required<Pick<BlurViewProps, 'intensity' | 'tint'>>): Record<string, string> {
+  const blur = `saturate(180%) blur(${Math.min(intensity, 100) * 0.2}px)`;
+  return {
     backgroundColor: getBackgroundColor(Math.min(intensity, 100), tint),
+    backdropFilter: blur,
+    WebkitBackdropFilter: blur,
   };
-
-  if (isBlurSupported()) {
-    const blur = `saturate(180%) blur(${Math.min(intensity, 100) * 0.2}px)`;
-    style.backdropFilter = blur;
-    // Safari support
-    style.WebkitBackdropFilter = blur;
-  }
-
-  return style;
 }
+
+export default BlurView;

packages/expo-blur/src/__tests__/BlurView-test.web.tsx

@@ -32,17 +32,6 @@ it(`prefers filters to background color`, () => {
   expect(view.style['backdropFilter']).toBeDefined();
 });
 
-it(`uses a transparent background color when filters aren't supported`, () => {
-  // @ts-ignore
-  global.CSS = undefined;
-
-  const withoutNativeBlur = render(<BlurView tint="light" testID="blur" />);
-  const view = getByTestId(withoutNativeBlur.container, 'blur');
-
-  expect(view.style['backdropFilter']).toBeUndefined();
-  expect(view.style['backgroundColor']).toBeDefined();
-});
-
 it(`supports Animated API`, () => {
   // react-native-web 0.11 doesn't support createAnimatedComponent with functional components.
   // This test ensures that the current version of RNW in Expo works with expo-blur.