JSFiddle - React, Tailwind, and code Playground

by jfriend00

HTML

Min Value: <input id="minRange" type="text" value="1"><br>
Max Value: <input id="maxRange" type="text" value="37"><br>
<button id="go" onclick="makeRandoms()">Generate Six Randoms</button><br><br><br>
<div id="output"></div>

JavaScript

function randCalc(maxVal, minVal, numRandoms) {
    var max = Math.max(maxVal, minVal);
    var min = Math.min(maxVal, minVal);
    // create a set to keep track of numbers we've already used so
    // we don't repeat any random numbers
    var set = {};
    var randoms = [];
    var rand;
    // prevent infinite loop if not given enough range
    if (max - min < numRandoms) {
        return randoms;
    }
    while (randoms.length < numRandoms) {
        rand = Math.floor((Math.random() * (max - min + 1) + min));
        // if we haven't already used this random number
        // then put it in our output array and add it to the set
        if (!(rand in set)) {
            randoms.push(rand);
            set[rand] = true;
        }
    }
    return randoms;
}

function makeRandoms() {
    // retrieve DOM values and convert them to numbers
    var maxVal = document.getElementById("maxRange").value;
    var minVal = document.getElementById("minRange").value;
    if (!maxVal || !minVal) {
        alert("You must specify both a minimum and maximum value");
        return;
    }
    // convert both to numbers
    maxVal = parseInt(maxVal, 10);
    minVal = parseInt(minVal, 10);
    if (minVal < 1) {
        alert("The min value cannot be lower then 1");
        return;
    }
    if (maxVal > 37) {
        alert("The higher value cannot be higher then 37");
        return;
    }
    if (maxVal - minVal < 6) {
        alert("The difference cannot be lower then 6");
        return;
    }
    var randoms = randCalc(maxVal, minVal, 6);
    // output the randoms array here
    document.getElementById("output").innerHTML = JSON.stringify(randoms);
}