JSFiddle - React, Tailwind, and code Playground

by Sherali Turdiyev

JavaScript

var array = [
    [1, 2],
    [1, 3],
    [3, 4]
];

function getArray(arr) {
    var t = arr.join("_"),
        k = 0,
        r = [];

    do {
        r.push(t[k ? ++k : k++]);
    } while (k = t.indexOf("_", k), k !== -1)
    return r;
}
console.log(getArray(array));