React事件节流效果失效的原因及解决

render() {
    return (
      <div className="search-bar">
        <input className="search-input" type="text" placeholder="请输入要搜索的用户名(英文)" onKeyDown={this.throttle(this.handleKeyDown)}/>
      </div>
    )
  }

throttle = (fn) => {
    let valid = true
    const context = this

    return function() {
      if (!valid) return
      valid = false

      const args = arguments

      fn.apply(context, args)

      setTimeout(() => {
        valid = true
      }, 1000);
    }
  }

  handleKeyDown = (e) => {
    let { value } = e.target
    const keyCode = e.keyCode

    if (keyCode !== 13) return

    if (!value.trim()) return
    
    // 发送搜索
    this.props.search(value)
  }

throttle = (fn) => {
    console.log('%c throttle初始化', 'color: red');
    let valid = true
    const context = this

    return function() {
      if (!valid) return
      valid = false

      const args = arguments

      fn.apply(context, args)

      setTimeout(() => {
        valid = true
      }, 1000);
    }
  }

render() {
    return (
      <div className="search-bar">
        <input className="search-input" type="text" placeholder="请输入要搜索的用户名(英文)" onKeyDown={this.handleKeyDown}/>
      </div>
    )
  }

handleKeyDown = this.throttle((e) => {
    let { value } = e.target
    const keyCode = e.keyCode

    if (keyCode !== 13) return

    if (!value.trim()) return
    
    // 发送搜索
    this.props.search(value)
  })

render() {
    return (
      <div className="search-bar">
        <input className="search-input" type="text" placeholder="请输入要搜索的用户名(英文)" onKeyDown={this.handleKeyDown}/>
      </div>
    )
  }

constructor(props) {
    super(props)
    this.handleKeyDown = this.throttle(this.handleSearch)
  }

  handleSearch = (e) => {
    let { value } = e.target
    const keyCode = e.keyCode

    if (keyCode !== 13) return

    if (!value.trim()) return
    
    // 发送搜索
    this.props.search(value)
  }