Masking last 4 digits in JavaScript

Question

Here I am using regex pattern to mask last 4 digits for Credit Card number.

$(\"#ccnumber\").html(ccnbr); //ccnumber refers to div ID

$(\"#ccnumber\").text(         


        

Answer 1

You can use:

str = str.replace(/\d(?=\d{4})/g, "*");

to mask all but last 4 digits in a given number of more than 4 digits.

RegEx Demo

Explanation:

• This reges uses a positive lookahead (?=\d{4}) which means match should be followed by 4 digits.
• \d matches a single digit with above lookahead condition and replaces that by *