String methods # 19

replace()

replace() method takes two arguments, the first argument is which character(s) or word do we wanna change, and the second argument is by which argument we wanna change.

const reg = new RegExp("Mozahedul", "i");
const str = "Mozahedul Islam is a good programmer";
console.log(reg);
// Return:
// /Mozahedul/i

const result = str.replace(reg, "Rafiqul");
console.log(result);
// Return:
// Rafiqul Islam is a good programmer

match() method

So far, we have only been checking if a pattern exists or not within a string with the .test() method. We can also extract the actual matches you found with the .match() method.

To use the .match() method, apply the method on a string and pass in the regex inside the parentheses.

Here's an example:

"Hello, World!".match(/Hello/);
let ourStr = "Regular expressions";
let ourRegex = /expressions/;
ourStr.match(ourRegex);

Here the first match would return ["Hello"] and the second would return ["expressions"]. Note that the .match syntax is the "opposite" of the .test method you have been using thus far:

'string'.match(/regex/);
/regex/.test('string');