JSFiddle - React, Tailwind, and code Playground

HTML

<div id="foo"></div>

JavaScript

var keys = [], x, total = 0;
while(total < 32) {
    x = Math.floor(Math.random() * 64);
    // way faster that looping through the array to check if it exists
    if(keys[x] == undefined) { 
        keys[x] = 1;
        total++;
    }
}
var numbers = [];
for(x in keys) numbers.push(x);
document.getElementById('foo').innerHTML = numbers.join(', ');
console.log(numbers);