Processing map latitude and longitude, reserved six decimal places

Filtered String, Boolean, Undefined, Null type, the user input is returned to the process and remains Number Type 6

longlatitude function (longLatVal) { 

            //处理NaN类型
            const longlat = parseFloat (longLatVal); 
            if (isNaN (longlat)) { 
                return 0; 
            } 

            //小数点保留六位
            const longlatsplit = longLatVal.split ( '.'); 
            if (longlatsplit.length> = 2) { 
                return parseFloat (longlatsplit [0] === ""? 0: longlatsplit [0]) + parseFloat ( "." + longlatsplit [1] .slice (0, 6)); 
            } 

            Return longlat; 
        } 
Longlatitude ( '') // 0 
longlatitude ( '非number') // 0 
longlatitude ( '0001') //0.001
longlatitude ( '001001') //1.001
longlatitude (001.001.0001) //1.001 
longlatitude ( '001.001000000.0001') //1.001