replace symbol from string using regex javascript code example

Example 1: replace all js

let a = 'a a a a aaaa aa a a';
a.replace(/aa/g, 'bb');
// => "a a a a bbbb bb a a"

Example 2: how to replace all the string in javascript when the string is javascript variable

function name(str,replaceWhat,replaceTo){
    var re = new RegExp(replaceWhat, 'g');
    return str.replace(re,replaceTo);
}