const scanner={
    /**
     * 监听document的扫描枪活动，扫描后调用doFunc执行，doFunc(str)
     * str是扫到的内容，在doFunc内执行
     * @param doFunc
     */
    monitorScan:function(doFunc){
        let tightInputInterval=50;
        let leastCodeLength=3;
        let lastPressedAt=0;
        let scannedStr="";
        $(document).on('keyup',function(e){
            let nowAtMilli=(new Date()).getTime();
            let inputInterval=nowAtMilli-lastPressedAt;
            if (inputInterval<tightInputInterval){
                if(e.key!=='Enter'){
                    scannedStr+=e.key;
                }else{
                    if(scannedStr.length>=leastCodeLength){
                        doFunc(scannedStr);
                    }
                    scannedStr='';
                }
            }else{
                if(e.key!=='Enter'){
                    scannedStr=e.key;
                }else{
                    scannedStr='';
                }
            }
            lastPressedAt=nowAtMilli;
        })
    },
    monitorFocusingTarget:function(doFunc){
        $('input').on('focus',function(e){
            doFunc(e.target);
        })
    },
};
module.exports=scanner;