String

String()

<script>
document.getElementById("demo").innerHTML =
String(new Date()) + "<br>" +
String("12345") + "<br>" +
String(12345);
</script>

Wed Mar 22 2023 11:59:44 GMT+0200 (за східноєвропейським стандартним часом)
12345
12345

parseInt()

<script>
document.getElementById("demo").innerHTML =
parseInt("10") + "<br>" +
parseInt("10.00") + "<br>" +
parseInt("10.33") + "<br>" +
parseInt("34 45 66") + "<br>" +
parseInt("   60   ") + "<br>" +
parseInt("40 years") + "<br>" +
parseInt("He was 40");
</script>

10
10
10
34
60
40
NaN

parseFloat()

<script>
document.getElementById("demo").innerHTML =
parseFloat(10) + "<br>" +
parseFloat("10") + "<br>" +
parseFloat("10.33") + "<br>" +
parseFloat("34 45 66") + "<br>" +
parseFloat("He was 40");
</script>

10
10
10.33
34
NaN

https://developer.mozilla.org/ru/docs/Web/JavaScript/Reference/Global_Objects/String