react setState是同步还是异步

changeDate = () => {
    const { count } = this.state
    this.setState({
      count: count+1
    })
    console.log(this.state.count)
  }
  render () {
    const { count } = this.state
    return (
      <>
        setState是同步还是异步
        <button onClick={this.changeDate}>更新count: {count}</button>
      </>
    )
  }

changeDate = () => {
    const { count } = this.state
    this.setState({
      count: count+1
    }, () => {
      console.log(this.state.count)
    })
  }
  render () {
    const { count } = this.state
    return (
      <>
        setState是同步还是异步
        <button onClick={this.changeDate}>更新count: {count}</button>
      </>
    )
  }

async changeDate(){
    await this.setStateAsync ({count: this.state.count+1})
    console.log(this.state.count)
  }
  setStateAsync (state) {
    return new Promise((resolve) => {
      this.setState(state,resolve)
    })
  }
  render () {
    const { count } = this.state
    return (
      <>
        setState是同步还是异步
        <button onClick={this.changeDate.bind(this)}>更新count: {count}</button>
      </>
    )
  }