HooksError

js

import React, { useState } from 'react'

function AppHooks() {

  const [list, setList] = useState([])


  function run() {
    setInterval(() => {
      list.push(Math.random())
      setList([...list])
    }, 1000)
  }

  return (
    <div>
      {list.length}
      <button onClick={ () => run() }>Run</button>
    </div>
  );
}


class AppClass extends React.Component {
  state = {
    list: []
  }

  run() {
    setInterval(() => {
      let list = this.state.list
      list.push(Math.random())
      this.setState({
        list
      })
    }, 1000)
  }

  render() {
    return (
      <div>
        {this.state.list.length}
        <button onClick={ () => this.run() }>Run</button>
      </div>
    )
  }
}


function App() {
  return (
    <React.Fragment>
      <h1>Hooks</h1>
      <AppHooks />
      <h1>Class</h1>
      <AppClass />
    </React.Fragment>
  )
}
export default App