react-native-worklets/src/runtimeKind.ts

The React Native multithreading library

'use strict';

export enum RuntimeKind {
  /**
   * The React Native runtime, which is the main runtime for React Native where
   * React exists and where components are rendered.
   */
  ReactNative = 1,
  /**
   * The UI runtime, which is a special runtime that executes on the UI thread,
   * mostly used for animations and gestures.
   */
  UI = 2,
  /** Additional runtime created on-demand by the user. */
  Worker = 3,
}

/**
 * Programmatic way to check the current runtime kind. It's useful when you need
 * specific implementations for different runtimes created by Worklets.
 *
 * For more optimized calls you can check the value of
 * `globalThis.__RUNTIME_KIND` directly.
 *
 * @returns The kind of the current runtime.
 */
export function getRuntimeKind(): RuntimeKind {
  'worklet';
  return globalThis.__RUNTIME_KIND;
}

if (globalThis.__RUNTIME_KIND === undefined) {
  // In Jest environments eager imports make this file to evaluate before
  // `initializers.ts` file, therefore we have to set the RuntimeKind here,
  // just to be safe.
  globalThis.__RUNTIME_KIND = RuntimeKind.ReactNative;
}