How to make this code as a library to use in main code

I have made a code to read data from a device then confert the data to be readable. Now my co-worker told me to make it as a library so he can get the data from it, but I just learn javascript and node.js so I don’t know how.

This is my code:

// create an empty modbus client
const ModbusRTU = require("modbus-serial");
const client = new ModbusRTU();
let timeoutRunRefHoldings = null;
// open connection to a serial port
client.connectRTUBuffered("/dev/ttyUSB0", { baudRate: 9600 })
    .then(setClient1)
    .then(function() {
        console.log("Connected"); })


async function setClient1() {
    // set the client's unit id
    // set a timout for requests default is null (no timeout)
    client.setID(1);

    // run program

console.log("Flow rate:", await ReadReg(0,2) + " m³/h");
console.log("Velocity:", await ReadReg(4,2) + " m/s"),
console.log("Fluid sound speed:", await ReadReg(6,2) + " m/s");
console.log("Temperature #1/inlet:", await ReadReg(32,2) + " °C");
console.log("Temperature #2/inlet:", await ReadReg(34,2) + " °C");
}

async function ReadReg(addr, len) {
    let regVal = await client.readHoldingRegisters(addr, len)
    return REAL4(...regVal.data)
}
 

function REAL4(reg1, reg2){
// i) Convert the first register into binary
    const value1=parseInt(reg1,10);
    var binaryVl1=value1.toString(2);
    while (binaryVl1.length < 16) {
        binaryVl1 = '0'+binaryVl1;
    }  
// ii) Convert the second register into binary 
    const value2=parseInt(reg2,10);
    var binaryVl2=value2.toString(2);
    while (binaryVl2.length < 16) {
        binaryVl2 = '0'+binaryVl2;
    }
// iii) Combine Reg1 & Reg2
    const combine=binaryVl2+binaryVl1;
    const cb16x=(parseInt(combine, 2)).toString(16);

    const buffer = new ArrayBuffer(4);
    const bytes = new Uint8Array(buffer);
    bytes[0] = '0x'+cb16x.substring(0,2);
    bytes[1] = '0x'+cb16x.substring(2,4);
    bytes[2] = '0x'+cb16x.substring(4,6);
    bytes[3] = '0x'+cb16x.substring(6);
// iv) Convert combine into float(IEEE 754 floating point)
    var view = new DataView(buffer);
    const result=(view.getFloat32(0, false)).toPrecision(6);
    return(result);
}

So, if I have to make it into a library should I remove console.log ?
I really don’t know anything about libraries.