Answers for "in javascript in a if statement changing string into a number"

how to change a string to number in javascript

let theInt = parseInt("5.90123"); //5
let theFloat = parseFloat("5.90123"); //5.90123

string to number javascript

new Number(valeur);
var a = new Number('123'); // a === 123 donnera false
var b = Number('123'); // b === 123 donnera true
a instanceof Number; // donnera true
b instanceof Number; // donnera false