Most of the time, operators and functions automatically convert the values given to them to the right type.
let value = true;
alert(typeof value); // boolean
value = String(value); // now value is a string "true"
alert(typeof value); // string
<!DOCTYPE HTML>
<html>
<body>
<p>Before the script...</p>
<script>
alert(Boolean(1)); // true
alert(Boolean(0)); // false
alert(Boolean("hello")); // true
alert(Boolean("")); // false
</script>
<p>...After the script.</p>
</body>
</html>