find and replace string javascript code example

Example 1: 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 2: javascript replace

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"

console.log(p.replace('dog', 'cow'));
// If pattern is a string, only the first occurrence will be replaced.
//output: "cow dog 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 !"