React mistakes

App.js

import { useEffect, useState } from 'react'

export default function App() {
  const [title, setTitle] = useState({
    firstTitle: 'Java',
    secondTitle: 'Script',
    renderCount: {
      value: 0, // this will increase by 1 every time the button is clicked
      comment: 'The count value preserves the count of the clicks.' // a constant. no change ever.
    },
    meta: {
      renderDate: new Date().toLocaleDateString(), // this will remain a constant between clicks (and renders).
      renderTime: new Date().toLocaleTimeString() // this will also remain the same.
    }
  })

  useEffect(() => console.log(JSON.stringify(title, null, 2)), [title])

  const handleClick = () => setTitle(prevState => ({
    ...prevState,
    firstTitle: 'React',
    secondTitle: 'JS',
    renderCount: {
      ...prevState.renderCount,
      value: prevState.renderCount.value + 1
    }
    // no need for `meta: { ...prevState.meta }` because it's not being updated.
  }))

  const handleClickNoIncrement = () => setTitle(prevState => ({
    ...prevState,
    firstTitle: 'React',
    secondTitle: 'JS',
  }))

  return (
    <div style={{ display: 'flex', gap: '3px', flexDirection: 'column', alignItems: 'flex-start' }}>
      <h2>{title.firstTitle + ' ' + title.secondTitle}</h2>
      <button onClick={handleClick}>Set title to React JS</button>
      <button onClick={handleClickNoIncrement}>Set title to React JS (no increment)</button>
    </div>
  )
}