Day 7: Regular Expressions II

Task

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

String starts with the prefix Mr., Mrs., Ms., Dr., or Er.
The remainder of string (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

Output Format

The function must return a RegExp object that matches any string 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.