R2D2

write_packet.js

let writePacket = (characteristic, buff, waitForNotification=false, timeout=0) => {
    return new Promise(function(resolve, reject) {

        let dataRead = [];

        let checkIsAValidRequest = (dataRead) => {
            if (dataRead[5] != 0x00) {
                characteristic.removeListener('data', listenerForRead);
                reject(dataRead[5]);
            }
        }

        let finish = () => {
            setTimeout(() => {
                characteristic.removeListener('data', listenerForRead);
                resolve(true);
            }, timeout);
        }

        let listenerForRead = (data, isNotification) => {
            dataRead.push(...data)
            if (data[data.length - 1] === EOP) {
                if (waitForNotification) {
                    if (dataRead[1] % 2 == 0) {
                        finish();
                    } else {
                        checkIsAValidRequest(dataRead);
                    }
                } else {
                    checkIsAValidRequest(dataRead);
                    finish();
                }
                dataRead = [];
            }
        };
        characteristic.on('data', listenerForRead);
        characteristic.write(Buffer.from(buff));
    });
}