how to replace all string in js code example

Example 1: str replace javascript all

str.replace(/abc/g, '');

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);
}