JSFiddle - React, Tailwind, and code Playground

JavaScript

$("body").append(diasHorario(2)); // seleciona Terça

function diasHorario(index) {
    var select = document.createElement('select');
    select.id = 'diasHorario';
    select.classList.add('form-control');
    var dias = ['Segunda', 'Terça', 'Quarta', 'Quinta', 'Sexta', 'Sábado', 'Domingo'];
    dias.forEach(function (dia, i) {
        var option = document.createElement('option');
        option.value = i + 1;
        option.innerHTML = dia;
        if (i == index -1) option.setAttribute('selected', 'selected');
        select.appendChild(option);
    });
    var wrapper = document.createElement('div');
    wrapper.appendChild(select);
    return wrapper.innerHTML;
}