javascript, use of prompt to gather data

Question

<script type="text/javascript">

        /* calcular a media de 4 notas */


        var n1 = 10
        var n2 = 10
        var n3 = 10
        var n4 = 10

        var media = (n1+n2+n3+n4)/4

        document.write("Sua média:", media);

</script>

Next, I wanted to use the Prompt mdn to type variables, instead of leaving them preset.

I also wanted to create a function to type some predefined texts, instead of using document.write() all the time.

I’m a beginner, if you can help me, thank you!

Answer 1

Since the promprt, like the alert, blocks code execution you can do it like this:

const nrDeNotas = 4; // talvez no futuro isto também seja um prompt('Quantas notas?');

const notas = Array(nrDeNotas)
  .fill()
  .map((_, i) => prompt('Insira a nota nr ' + (i + 1)))
  .map(Number);

const media = notas.reduce((soma, nota) => soma + nota, 0) / nrDeNotas;
document.write('A média é de ' + media + ' valores');

You can do it with less code but it might get harder to read:

const media = ['', '', '', ''].reduce((soma, nota, i, arr) => soma + Number(prompt('Insira uma nota')) / arr.length, 0);
document.write('A média é ' + media);