replace text from string javascript code example

Example 1: javascript replace string

var str = "JavaScript replace method test";
var res = str.replace("test", "success");  
//res = Javscript replace method success

Example 2: replace all occurrences of a string in javascript

const p = 'dog dog cat rat';

const regex = /dog/gi;

console.log(p.replace(regex, 'cow'));
//if pattern is regular expression all matches will be replaced
//output: "cow cow cat rat"

Example 3: replace in string javascript

const p = 'hello world ! hello everyone ! ';

const regex = /hello/gi;

console.log(p.replace(regex, 'good morning'));
// expected output: "good morning world ! good morning everyone !"

console.log(p.replace('hello', 'good evening'));
// expected output: "good evening world ! hello everyone !"