replace \\x with \x javascript code example

Example 1: string replace javascript

let re = /apples/gi; 
let str = "Apples are round, and apples are juicy.";
let newstr = str.replace(re, "oranges"); 
console.log(newstr)

output:

"oranges are round, and oranges are juicy."

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

function name(str,replaceWhat,replaceTo){
    replaceWhat = replaceWhat.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&');
    var re = new RegExp(replaceWhat, 'g');
    return str.replace(re,replaceTo);
}