# Day 7: Regular Expressions II | 10 Days Of JavaScript | HackerRank Solution

Hello coders, today we are going to solve Day 7: Regular Expressions II HackerRank Solution which is a part of 10 Days Of JavaScript Series.

Contents

Complete the function in the editor below by returning a RegExp object, re, that matches any string s satisfying both of the following conditions:

• String s starts with the prefix `Mr.``Mrs.``Ms.``Dr.`, or `Er.`
• The remainder of string s (i.e., the rest of the string after the prefix) consists of one or more upper and/or lowercase English alphabetic letters (i.e., `[a-z]` and `[A-Z]`).

## Constraints

• The length of string s is =>3.

## Output Format

The function must return a RegExp object that matches any string s satisfying both of the given conditions.

Sample Input 0

`Mr.X`

Sample Output 0

`true`

Explanation 0

This string starts with `Mr.`, followed by an English alphabetic letter (`X`).

Sample Input 1

`Mrs.Y`

Sample Output 1

`true`

Explanation 1

This string starts with `Mrs.`, followed by an English alphabetic letter (`Y`).

Sample Input 2

`Dr#Joseph`

Sample Output 2

`false`

Explanation 2

This string starts with `Dr#` instead of `Dr.`, so it’s invalid.

Sample Input 3

`Er .Abc`

Sample Output 3

`false`

Explanation 3

This string starts with `Er` but there is a space before the period (`.`), making the string invalid.

## Solution -Day 7: Regular Expressions II

```'use strict';

process.stdin.resume();
process.stdin.setEncoding('utf-8');

let inputString = '';
let currentLine = 0;

process.stdin.on('data', inputStdin => {
inputString += inputStdin;
});

process.stdin.on('end', _ => {
inputString = inputString.trim().split('\n').map(string => {
return string.trim();
});

main();
});

return inputString[currentLine++];
}

function regexVar() {
/*
* Declare a RegExp object variable named 're'
* It must match a string that starts with 'Mr.', 'Mrs.', 'Ms.', 'Dr.', or 'Er.',
* followed by one or more letters.
*/
let re = /^(Mr|Mrs|Ms|Dr|Er)(\.)([a-zA-Z])+\$/;
/*
* Do not remove the return statement
*/
return re;
}

function main() {
const re = regexVar();