JSFiddle - React, Tailwind, and code Playground

JavaScript

var colors = [];

function getRandUniqColor()
{
    var r = getRGBString(),
        g = getRGBString(),
        b = getRGBString(),
        rgb = r + g + b;

    if ( colors.indexOf(rgb) == -1 )
    {
        colors.push(rgb);
        return {
            r: r,
            g: g,
            b: b
        }
    }
    else
    {
        return getRandUniqColor()
    }
}

function getRGBString()
{
    var str = Math.floor(Math.random()*255).toString();
    while (str.length < 3)
    {
        str = '0' + str;
    }
    return str;
}






// Just to generate the samples

var i = 0, rgb, html = '';

while (i < 40)
{
    rgb = getRandUniqColor();
    rgb = "rgb(" + +rgb.r + "," + +rgb.g + "," + +rgb.b + ")";
    html += '<span style="background:' + rgb + '">' + rgb + '</span><br />';

    i++;
}
$('body').append(html);