How to generate a random values periodically and publish it using MQTT protocol?

I want to repletely generate different random values for every 1 second and publish it to MQTT protocol. The code is working but it is keep sending the last value how to make it that it will send a different value every 1 second?

var mqtt = require('mqtt')

var Broker_URL = 'mqtt://localhost';
var client  = mqtt.connect(Broker_URL);

var MIN_PER_RANK =75
var MAX_PER_RANK =100

client.on('connect', function () {
    console.log("MQTT connected  "+ client.connected);
})

class virtualsensor {
    
    sendStateUpdate (newdata) {
        client.publish("testtopic", newdata)
    }
}

let vs = new virtualsensor()

let newdata = '';

for (var i=0; i<5; i++){
    newdata= String(Math.floor(Math.random() * (MAX_PER_RANK - MIN_PER_RANK  + 1) + MIN_PER_RANK));
    vs.sendStateUpdate(newdata)
}

var interval = setInterval(function(){vs.sendStateUpdate(newdata)},1000);

the output:

testtopic 81
testtopic 76
testtopic 89
testtopic 100
testtopic 96
testtopic 96
testtopic 96
testtopic 96
testtopic 96
testtopic 96
testtopic 96
testtopic 96
testtopic 96

Thanks in advance.