Сrc8 control

I use the library by the simple code:

var crc8 = require("crc8").connect();

var dt = '{"ab":22}';
var codeddt = crc8.encode(dt);
// > {"ab":22}212#135

var decdt = crc8.decode(codeddt);
console.log("crc8 Report = ", decdt);
// > crc8 Report =  {"ab":22}
if (decdt.indexOf("CRC") > 0 ){
    return;
}
else {
    // yours code 
}