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react addEventListener监听键盘事件实现扫码枪输入(转)

程序员文章站 2022-06-14 22:27:38
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转载链接 https://blog.csdn.net/wjy199506/article/details/78885289

componentDidMount() {
    var code = "";
    var lastTime,nextTime;
    var lastCode,nextCode;
    window.addEventListener('keypress',function(e){
      nextCode = e.which;
      nextTime = new Date().getTime();

      if(lastCode != null && lastTime != null && nextTime - lastTime <= 30) {
          code += String.fromCharCode(lastCode); 
      } else if(lastCode != null && lastTime != null && nextTime - lastTime > 100){
          code = "";
      }

      lastCode = nextCode;
      lastTime = nextTime;
      if(e.which == 13){
        console.log(code);
        code = "";
      }       
    })
  }