Replace function in string in javascript

var str = "JavaScript replace method test";
var res = str.replace("test", "success");  
//res = Javscript replace method successvar res = str.replace("find", "replace");var str = "Original string!";
var str = str.replace("Original", "New");let string = 'soandso, my name is soandso';

let replaced = string.replace(/soandso/gi, 'Dylan');

console.log(replaced); //Dylan, my name is Dylanvar str = "Hello World";
var res = str. reaplace("World", "Simon");
output result = Hello simon