"Utilize Regular Expressions to conceal part of a text string with a

Question

"Utilize Regular Expressions to conceal part of a text string with a

Looking for a way to conceal part of a string using JavaScript?

For example, wanting to mask the second and third segments of a credit card number like this using regex:

4567 6365 7987 3783 → 4567 **** **** 3783
3457 732837 82372 → 3457 ****** 82372

The goal is to retain only the first 4 digits and the last 5 characters.

Here's what I've tried so far: /(?!^.*)[^a-zA-Z\s](?=.{5})/g

https://regex101.com/r/ZBi54c/2

javascript regex mask credit-card

Answer 1

Answer №1

If you're looking to mask a credit card number, here's a simple solution:

const creditCardNumber = '1234 5678 9101 1121';
const firstFour = creditCardNumber.substring(0, 4);
const lastFour = creditCardNumber.substring(creditCardNumber.length - 4);

const maskedNumbers = creditCardNumber.substring(4, creditCardNumber.length - 4).replace(/\d/g,"*");
console.log(firstFour + maskedNumbers + lastFour);

Answer 2

If you're looking to mask a credit card number, here's a simple solution:

const creditCardNumber = '1234 5678 9101 1121';
const firstFour = creditCardNumber.substring(0, 4);
const lastFour = creditCardNumber.substring(creditCardNumber.length - 4);

const maskedNumbers = creditCardNumber.substring(4, creditCardNumber.length - 4).replace(/\d/g,"*");
console.log(firstFour + maskedNumbers + lastFour);

Answer 3

Answer №2

You can take the first four digits and substitute the remaining ones.

console.log(
    ['4567 6365 7987 3783', '3457 732837 82372'].map(
        s => s.slice(0, 4) + s.slice(4).replace(/\d(?=.* )/g, '*')
    )
);

Answer 4

You can take the first four digits and substitute the remaining ones.

console.log(
    ['4567 6365 7987 3783', '3457 732837 82372'].map(
        s => s.slice(0, 4) + s.slice(4).replace(/\d(?=.* )/g, '*')
    )
);

Answer 5

Answer №3

The original poster seems satisfied with the answer provided. I have come up with an alternative solution that utilizes just regular expressions:

function maskNumbers(match, group1, group2, group3) {
  var maskedNums = group2.replace(/\d/g, '*');
  return group1 + " " + maskedNums + " " + group3;
}

function maskCreditCardNumbers(str) {
  var regex = /(\d{4})\s(\d{4}\s\d{4}|\d{6})\s(\d{4}|\d{5})/;

  if (regex.test(str))
    return str.replace(regex, maskNumbers);
  else return "";
}


var cardNumber1 = "4567 6365 7987 3783";
var cardNumber2 = "3457 732837 82372";
var textString = "dfdf dfdf";
console.log(maskCreditCardNumbers(cardNumber1));
console.log(maskCreditCardNumbers(cardNumber2));
console.log(maskCreditCardNumbers(textString));

This approach ensures that the pattern is matched before any replacements are attempted. For instance, in the third test scenario, it outputs an empty string as expected. The regular expression can be modified to accommodate additional credit card number formats beyond those specified in the initial query.

Answer 6

The original poster seems satisfied with the answer provided. I have come up with an alternative solution that utilizes just regular expressions:

function maskNumbers(match, group1, group2, group3) {
  var maskedNums = group2.replace(/\d/g, '*');
  return group1 + " " + maskedNums + " " + group3;
}

function maskCreditCardNumbers(str) {
  var regex = /(\d{4})\s(\d{4}\s\d{4}|\d{6})\s(\d{4}|\d{5})/;

  if (regex.test(str))
    return str.replace(regex, maskNumbers);
  else return "";
}


var cardNumber1 = "4567 6365 7987 3783";
var cardNumber2 = "3457 732837 82372";
var textString = "dfdf dfdf";
console.log(maskCreditCardNumbers(cardNumber1));
console.log(maskCreditCardNumbers(cardNumber2));
console.log(maskCreditCardNumbers(textString));

This approach ensures that the pattern is matched before any replacements are attempted. For instance, in the third test scenario, it outputs an empty string as expected. The regular expression can be modified to accommodate additional credit card number formats beyond those specified in the initial query.

Answer 7

Answer №4

I wanted to provide additional insight on the response given by @Nina Scholz. In the code snippet below, I demonstrate how I utilize the .slice() method to mask a variable under two conditions.

Firstly, we have a simple variable: var n = '12345567890'
Secondly, an array object is used

// Masking a single number
var n = '601115558888';
var singleNumber = n.slice(0, 4) + n.slice(4, n.length -4).replace(/\d/g,'*') + n.slice(n.length -4);
console.log(singleNumber);

// Array of objects
var obj = [{
  contacts_name: 'Jason',
  contacts_num : '651231239991'
},
{
  contacts_name: 'King',
  contacts_num : '60101233321'
}];

// Masking the middle numbers, displaying the first 4 digits and last 4 digits while replacing the rest with *
var num = obj.map((element, index) =>
  element.contacts_num.slice(0,4) 
   + element.contacts_num.slice(4, element.contacts_num.length-4).replace(/\d/g, '*')
   + element.contacts_num.slice(element.contacts_num.length -4)
);

console.log(num);

Answer 8

I wanted to provide additional insight on the response given by @Nina Scholz. In the code snippet below, I demonstrate how I utilize the .slice() method to mask a variable under two conditions.

Firstly, we have a simple variable: var n = '12345567890'
Secondly, an array object is used

// Masking a single number
var n = '601115558888';
var singleNumber = n.slice(0, 4) + n.slice(4, n.length -4).replace(/\d/g,'*') + n.slice(n.length -4);
console.log(singleNumber);

// Array of objects
var obj = [{
  contacts_name: 'Jason',
  contacts_num : '651231239991'
},
{
  contacts_name: 'King',
  contacts_num : '60101233321'
}];

// Masking the middle numbers, displaying the first 4 digits and last 4 digits while replacing the rest with *
var num = obj.map((element, index) =>
  element.contacts_num.slice(0,4) 
   + element.contacts_num.slice(4, element.contacts_num.length-4).replace(/\d/g, '*')
   + element.contacts_num.slice(element.contacts_num.length -4)
);

console.log(num);

Answer 9

Answer №5

If JavaScript is being used for regex masking, the approach is flawed. Ideally, JS should not have access to the original card number except when it is initially received from the user and sent to the server without any masking to allow for typo checks.

Unfortunately, the situation seems quite dire already.

On the server-side, if the card number is already separated by spaces*, one possible solution is: (shown in PHP but adaptable to other languages)

$parts = explode(" ", $fullnumber);
$first = array_shift($parts);
$last = array_pop($parts);
$middle = implode(" ", $parts);
$mask = preg_replace("/\d/", "*", $middle);
$result = "$first $mask $last";

^{* This format is not recommended}

Answer 10

If JavaScript is being used for regex masking, the approach is flawed. Ideally, JS should not have access to the original card number except when it is initially received from the user and sent to the server without any masking to allow for typo checks.

Unfortunately, the situation seems quite dire already.

On the server-side, if the card number is already separated by spaces*, one possible solution is: (shown in PHP but adaptable to other languages)

$parts = explode(" ", $fullnumber);
$first = array_shift($parts);
$last = array_pop($parts);
$middle = implode(" ", $parts);
$mask = preg_replace("/\d/", "*", $middle);
$result = "$first $mask $last";

^{* This format is not recommended}

"Utilize Regular Expressions to conceal part of a text string with a

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Similar questions

Error TS2322: Type 'boolean' cannot be assigned to type 'undefined'. What is the best approach for dynamically assigning optional properties?

What is the most effective approach for preventing the inadvertent override of other bound functions on window.onresize?

Facing Problem with Angular PUT Request - "Missing required request body"

Obtain a collection of strings from an array of objects based on specified criteria

Organize a collection of items in AngularJS

Unfortunately, we encountered an AJAX error while trying to access data from the website datatables.net. You can find

Create a form with Vue that generates input fields based on JSON data and

What methods can be used to broaden configuration variables within VSCode using an extension?

Create your own AngularJS directive for displaying or hiding elements using ng-show/ng

Transferring information from child to parent class in TypeScript

Optimal Placement of jQuery Event Handlers in React/Redux Components with Asynchronous Data Loading

A guide on implementing listings in React Native through the use of loops

When Ajax responseText and echo fail, the header file contents are sent back instead

What is the best way to turn each function within the module pattern into a promise?

invoke the modal function from a separate React file

The application is unable to recognize the CSS file

Troubleshooting Async Issues in Node.js

Incorporating a React element into a JavaScript object's property: A comprehensive guide

Angular is using the previous parameter value upon clicking the button

Setting the $dirty flag to true when a value is entered in the text box, but not the other way around