https://bsky.app/profile/zeta.vg/post/3kt23gnsky32u

index.js

import { useEffect } from 'react';
import registerRootComponent from 'expo/build/launch/registerRootComponent';

/* PASTE THE CODE HERE */

function App() {
  useEffect(() => {
    const timer = setTimeout(() => {
      const iterations = 1e6;

      const start = performance.now();
      for (let i = 0; i < iterations; i++) {
        fn();
      }
      const end = performance.now();

      console.log(`${end - start}ms`);
    }, 1000);

    return () => {
      clearTimeout(timer);
    };
  }, [fn]);

  return null;
}

registerRootComponent(App);

index_reanimated.js

import { useEffect } from 'react';
import { runOnUI } from 'react-native-reanimated';
import registerRootComponent from 'expo/build/launch/registerRootComponent';

/* PASTE THE CODE HERE, WITH 'worklet' inserted in fn. */

function test() {
  'worklet';
  const iterations = 1e6;

  const start = performance.now();
  for (let i = 0; i < iterations; i++) {
    fn();
  }
  const end = performance.now();

  console.log(`${end - start}ms`);
}

function App() {
  useEffect(() => {
    const timer = setTimeout(() => {
      runOnUI(test)();
    }, 1000);

    return () => {
      clearTimeout(timer);
    };
  }, [fn]);

  return null;
}

registerRootComponent(App);

test_1.js

const obj = {
  a: 1,
  b: 2,
  c: 3,
  d: 4,
};

function fn() {
  return obj.a;
}

test_2.js

const obj = {
  a: 1,
  b: 2,
  c: 3,
  d: 4,
};

const { a } = obj;

function fn() {
  return a;
}