Problem

Given a valid (IPv4) IP address, return a defanged version of that IP address.

A defanged IP address replaces every period “.” with “[.]”.

Example 1:

Input: address = “1.1.1.1”

Output: “1[.]1[.]1[.]1”

Example 2:

Input: address = “255.100.50.0”

Output: “255[.]100[.]50[.]0”

Constraints:

The given address is a valid IPv4 address.

Pre analysis

replacing ‘.’ with ‘[.]’

O(n)

Another solution

var defangIPaddr = function(address) {
    return address.replace(/\./g,"[.]");
};