str = str.replace(/\s/g, '');

var name = "codepadding code ";
// remove all white spaces single or multiple spaces
var name = name.replace(/\s/g, '');
console.log(name)
//output
//mizanurrahmanmizan

const removeAllSpaces = (string) => { const newText = string.replace(/\s+/g, ""); return newText
};
console.log(removeAllSpaces(" Hello World "));
//HelloWorld

console.log(' a b c d e f g '.replaceAll(' ',''));
//abcdefg

var string = "Javascript is fun";
var newString = string.replace(" ", "_");
console.log(newString); // Javascript_is_fun