.replace()

Searches a string for a string value, or a regular expression, and returns a new string where some or all matches are replaced.

string.replace(searchValue, replacementValue);

If the searchValue is a string then only the first instance of the value will be replaced. To replace all instances, use the global (g) modifier on a regular expression.

Replace 'cats' with 'rats':

const weather = `It's raining cats and dogs!`;

const replaceCatsWithRats = weather.replace('cats', 'rats');

console.log(replaceCatsWithRats);
// Output: It's raining rats and dogs!

Find and replace multiple matches:

const kidsBook = 'Brown bear, brown bear, what do you see?';

const birdsNotBears = kidsBook.replace(/bear/g, 'bird');

console.log(birdsNotBears);
// Output: Brown bird, brown bird, what do you see?