Ejemplo barra bootstrap

html

 <div class="progress">
        <div id="barra" class="progress-bar progress-bar-striped progress-bar-animated" style="width:10%"></div>
    </div>

jd

let barra = document.getElementById("barra")
let cont = 10
setTimeout(incrementarBarra, 1000)
function incrementarBarra() {
    cont+=5
    barra.style.width = cont + "%"
    barra.innerHTML = cont + "%"
    if (cont < 100) {
        setTimeout(incrementarBarra, 1000)
    }
}