[Web LA] Remove existingTransform (#6060)

## Summary

A while ago I've noticed that layout animations on mobile throw warning
if one tries to add animation into `View` that has `transform` property.
Now, while working on #5277 I've decided to remove code responsible for
applying existing transform on web. Here are the reasons why I believe
it is good idea:

1. It unifies behavior with mobile platforms, which are main target of
`reanimated`.
2. Some of `transforms` were not applied correctly and required
additional calculations to be implemented (like `skew`).
3. Removing existing transforms means removing a lot of `ifs` and
unnecessary code.

## Test plan

Tested on example app on `LA` examples.

src/reanimated2/layoutReanimation/web/animationParser.ts

@@ -1,7 +1,5 @@
 'use strict';
 
-import type { TransformsStyle } from 'react-native';
-
 export interface ReanimatedWebTransformProperties {
   translateX?: string;
   translateY?: string;
@@ -67,33 +65,3 @@ export function convertAnimationObjectToKeyframes(
 
   return keyframe;
 }
-
-export function convertTransformToString(
-  transform: NonNullable<TransformsStyle['transform']> | undefined
-) {
-  if (!transform) {
-    return '';
-  }
-
-  type RNTransformProp = (typeof transform)[number];
-
-  let transformString = '';
-
-  // @ts-ignore `transform` cannot be string because in that case
-  // we throw error in `extractTransformFromStyle`
-  transform.forEach((transformObject: RNTransformProp) => {
-    for (const [key, value] of Object.entries(transformObject)) {
-      if (key === 'reversed') {
-        continue;
-      }
-
-      if (key.indexOf('translate') < 0) {
-        transformString += `${key}(${value}) `;
-      } else {
-        transformString += `${key}(${value}px) `;
-      }
-    }
-  });
-
-  return transformString;
-}

src/reanimated2/layoutReanimation/web/animationsManager.ts

@@ -7,17 +7,13 @@ import type {
   LayoutAnimationStaticContext,
 } from '../../../createAnimatedComponent/commonTypes';
 import { LayoutAnimationType } from '../animationBuilder/commonTypes';
-import type { StyleProps } from '../../commonTypes';
-import { createAnimationWithExistingTransform } from './createAnimation';
 import {
-  extractTransformFromStyle,
   getProcessedConfig,
   handleExitingAnimation,
   handleLayoutTransition,
   setElementAnimation,
 } from './componentUtils';
 import { areDOMRectsEqual } from './domUtils';
-import type { TransformsStyle } from 'react-native';
 import type { TransitionData } from './animationParser';
 import { makeElementVisible } from './componentStyle';
 
@@ -58,32 +54,23 @@ function chooseAction(
   animationType: LayoutAnimationType,
   animationConfig: AnimationConfig,
   element: HTMLElement,
-  transitionData: TransitionData,
-  transform: TransformsStyle['transform'] | undefined
+  transitionData: TransitionData
 ) {
   switch (animationType) {
     case LayoutAnimationType.ENTERING:
-      setElementAnimation(element, animationConfig, transform);
+      setElementAnimation(element, animationConfig);
       break;
     case LayoutAnimationType.LAYOUT:
       transitionData.reversed = animationConfig.reversed;
-
-      handleLayoutTransition(
-        element,
-        animationConfig,
-        transitionData,
-        transform
-      );
+      handleLayoutTransition(element, animationConfig, transitionData);
       break;
     case LayoutAnimationType.EXITING:
       handleExitingAnimation(element, animationConfig);
       break;
   }
 }
 
-function tryGetAnimationConfigWithTransform<
-  ComponentProps extends Record<string, unknown>
->(
+function tryGetAnimationConfig<ComponentProps extends Record<string, unknown>>(
   props: Readonly<AnimatedComponentProps<ComponentProps>>,
   animationType: LayoutAnimationType
 ) {
@@ -96,35 +83,28 @@ function tryGetAnimationConfigWithTransform<
     typeof config.constructor;
 
   const isLayoutTransition = animationType === LayoutAnimationType.LAYOUT;
-  const initialAnimationName =
+  const animationName =
     typeof config === 'function'
       ? config.presetName
       : (config.constructor as ConstructorWithStaticContext).presetName;
 
   const shouldFail = checkUndefinedAnimationFail(
-    initialAnimationName,
+    animationName,
     isLayoutTransition
   );
 
   if (shouldFail) {
     return null;
   }
 
-  const transform = extractTransformFromStyle(props.style as StyleProps);
-
-  const animationName =
-    transform && animationType !== LayoutAnimationType.EXITING
-      ? createAnimationWithExistingTransform(initialAnimationName, transform)
-      : initialAnimationName;
-
   const animationConfig = getProcessedConfig(
     animationName,
     animationType,
     config as CustomConfig,
-    initialAnimationName as AnimationNames
+    animationName as AnimationNames
   );
 
-  return { animationConfig, transform };
+  return animationConfig;
 }
 
 export function startWebLayoutAnimation<
@@ -135,20 +115,14 @@ export function startWebLayoutAnimation<
   animationType: LayoutAnimationType,
   transitionData?: TransitionData
 ) {
-  const maybeAnimationConfigWithTransform = tryGetAnimationConfigWithTransform(
-    props,
-    animationType
-  );
-
-  if (maybeAnimationConfigWithTransform) {
-    const { animationConfig, transform } = maybeAnimationConfigWithTransform;
+  const animationConfig = tryGetAnimationConfig(props, animationType);
 
+  if (animationConfig) {
     chooseAction(
       animationType,
       animationConfig,
       element,
-      transitionData as TransitionData,
-      transform
+      transitionData as TransitionData
     );
   } else {
     makeElementVisible(element, 0);

src/reanimated2/layoutReanimation/web/componentUtils.ts

@@ -1,6 +1,5 @@
 'use strict';
 
-import type { TransformsStyle } from 'react-native';
 import { Animations, TransitionType, WebEasings } from './config';
 import type {
   AnimationCallback,
@@ -9,14 +8,12 @@ import type {
   CustomConfig,
   WebEasingsNames,
 } from './config';
-import { convertTransformToString } from './animationParser';
 import type { TransitionData } from './animationParser';
 import { TransitionGenerator } from './createAnimation';
 import { scheduleAnimationCleanup } from './domUtils';
 import { _updatePropsJS } from '../../js-reanimated';
 import type { ReanimatedHTMLElement } from '../../js-reanimated';
 import { ReduceMotion } from '../../commonTypes';
-import type { StyleProps } from '../../commonTypes';
 import { isReducedMotion } from '../../PlatformChecker';
 import { LayoutAnimationType } from '../animationBuilder/commonTypes';
 import type { ReanimatedSnapshot, ScrollOffsets } from './componentStyle';
@@ -86,27 +83,6 @@ function getReversedFromConfig(config: CustomConfig) {
   return !!config.reversed;
 }
 
-export function extractTransformFromStyle(style: StyleProps) {
-  if (!style) {
-    return;
-  }
-
-  if (typeof style.transform === 'string') {
-    throw new Error('[Reanimated] String transform is currently unsupported.');
-  }
-
-  if (!Array.isArray(style)) {
-    return style.transform;
-  }
-
-  // Only last transform should be considered
-  for (let i = style.length - 1; i >= 0; --i) {
-    if (style[i]?.transform) {
-      return style[i].transform;
-    }
-  }
-}
-
 export function getProcessedConfig(
   animationName: string,
   animationType: LayoutAnimationType,
@@ -144,8 +120,7 @@ export function saveSnapshot(element: HTMLElement) {
 
 export function setElementAnimation(
   element: HTMLElement,
-  animationConfig: AnimationConfig,
-  existingTransform?: TransformsStyle['transform']
+  animationConfig: AnimationConfig
 ) {
   const { animationName, duration, delay, easing } = animationConfig;
 
@@ -174,7 +149,6 @@ export function setElementAnimation(
     }
 
     element.addEventListener('animationcancel', animationCancelHandler);
-    element.style.transform = convertTransformToString(existingTransform);
   };
 
   if (!(animationName in Animations)) {
@@ -185,8 +159,7 @@ export function setElementAnimation(
 export function handleLayoutTransition(
   element: HTMLElement,
   animationConfig: AnimationConfig,
-  transitionData: TransitionData,
-  existingTransform: TransformsStyle['transform'] | undefined
+  transitionData: TransitionData
 ) {
   const { animationName } = animationConfig;
 
@@ -209,20 +182,10 @@ export function handleLayoutTransition(
 
   animationConfig.animationName = TransitionGenerator(
     animationType,
-    transitionData,
-    existingTransform
+    transitionData
   );
 
-  const transformCopy = existingTransform
-    ? structuredClone(existingTransform)
-    : [];
-
-  // @ts-ignore `existingTransform` cannot be string because in that case
-  // we throw error in `extractTransformFromStyle`
-  transformCopy.push(transitionData);
-  element.style.transform = convertTransformToString(transformCopy);
-
-  setElementAnimation(element, animationConfig, existingTransform);
+  setElementAnimation(element, animationConfig);
 }
 
 function getElementScrollValue(element: HTMLElement): ScrollOffsets {