react-native-reanimated/src/worklets/valueUnpacker.ts

More powerful alternative to Animated library for React Native.

/* eslint-disable reanimated/use-reanimated-error */
'use strict';
import type { WorkletFunction } from '../commonTypes';
import { isWorkletFunction } from '../commonTypes';
import { shouldBeUseWeb } from '../PlatformChecker';

function valueUnpacker(
  objectToUnpack: any,
  category?: string,
  remoteFunctionName?: string
): any {
  'worklet';
  let workletsCache = global.__workletsCache;
  let handleCache = global.__handleCache;
  if (workletsCache === undefined) {
    // init
    workletsCache = global.__workletsCache = new Map();
    handleCache = global.__handleCache = new WeakMap();
  }
  const workletHash = objectToUnpack.__workletHash;
  if (workletHash !== undefined) {
    let workletFun = workletsCache.get(workletHash);
    if (workletFun === undefined) {
      const initData = objectToUnpack.__initData;
      if (global.evalWithSourceMap) {
        // if the runtime (hermes only for now) supports loading source maps
        // we want to use the proper filename for the location as it guarantees
        // that debugger understands and loads the source code of the file where
        // the worklet is defined.
        workletFun = global.evalWithSourceMap(
          '(' + initData.code + '\n)',
          initData.location,
          initData.sourceMap
        ) as (...args: any[]) => any;
      } else if (global.evalWithSourceUrl) {
        // if the runtime doesn't support loading source maps, in dev mode we
        // can pass source url when evaluating the worklet. Now, instead of using
        // the actual file location we use worklet hash, as it the allows us to
        // properly symbolicate traces (see errors.ts for details)
        workletFun = global.evalWithSourceUrl(
          '(' + initData.code + '\n)',
          `worklet_${workletHash}`
        ) as (...args: any[]) => any;
      } else {
        // in release we use the regular eval to save on JSI calls
        // eslint-disable-next-line no-eval
        workletFun = eval('(' + initData.code + '\n)') as (
          ...args: any[]
        ) => any;
      }
      workletsCache.set(workletHash, workletFun);
    }
    const functionInstance = workletFun.bind(objectToUnpack);
    objectToUnpack._recur = functionInstance;
    return functionInstance;
  } else if (objectToUnpack.__init !== undefined) {
    let value = handleCache.get(objectToUnpack);
    if (value === undefined) {
      value = objectToUnpack.__init();
      handleCache.set(objectToUnpack, value);
    }
    return value;
  } else if (category === 'RemoteFunction') {
    const fun = () => {
      const label = remoteFunctionName
        ? `function \`${remoteFunctionName}\``
        : 'anonymous function';
      throw new Error(`[Reanimated] Tried to synchronously call a non-worklet ${label} on the UI thread.
See https://docs.swmansion.com/react-native-reanimated/docs/guides/troubleshooting#tried-to-synchronously-call-a-non-worklet-function-on-the-ui-thread for more details.`);
    };
    fun.__remoteFunction = objectToUnpack;
    return fun;
  } else {
    throw new Error(
      `[Reanimated] Data type in category "${category}" not recognized by value unpacker: "${_toString(
        objectToUnpack
      )}".`
    );
  }
}

type ValueUnpacker = WorkletFunction<
  [objectToUnpack: any, category?: string],
  any
>;

if (__DEV__ && !shouldBeUseWeb()) {
  const testWorklet = (() => {
    'worklet';
  }) as WorkletFunction<[], void>;
  if (!isWorkletFunction(testWorklet)) {
    throw new Error(
      `[Reanimated] Failed to create a worklet. See https://docs.swmansion.com/react-native-reanimated/docs/guides/troubleshooting#failed-to-create-a-worklet for more details.`
    );
  }
  if (!isWorkletFunction(valueUnpacker)) {
    throw new Error('[Reanimated] `valueUnpacker` is not a worklet');
  }
  const closure = (valueUnpacker as ValueUnpacker).__closure;
  if (closure === undefined) {
    throw new Error('[Reanimated] `valueUnpacker` closure is undefined');
  }
  if (Object.keys(closure).length !== 0) {
    throw new Error('[Reanimated] `valueUnpacker` must have empty closure');
  }
}

export function getValueUnpackerCode() {
  return (valueUnpacker as ValueUnpacker).__initData.code;
}