JSFiddle - React, Tailwind, and code Playground

JavaScript

var data = [1, 2, 3, 2]
var dump = [];
for (var i = 0; i < data.length; i++) {
    if (dump.length == 0) {
        dump.push(data[i])
    } else {
        for (var a = 0; a < dump.length; a++) {
            if (dump[a] == data[i]) {
                break;
            }
        }
        if (a == dump.length) dump.push(data[i]);
    }
}
console.log(dump)