Javascript Email Mask

emailmask.js

/* 
	Create a Mask in an email address
	This function create a mask using a valid email address.
	This is usefull when someone need to confirm the email used in a system
	Author: Gabriel Froes - https://gist.github.com/gabrielfroes
	===================================================================
	Update to show one char before @
 */
function emailMask(email: string) {
      var maskedEmail = email.replace(/([^@\.])/g, '*').split('')
      var previous = ''

      let j = 0
      for (let i = 0; i < maskedEmail.length; i++) {
        if (i <= 1 || previous === '.') {
          maskedEmail[i] = email[i]
        } else if (maskedEmail[i] === '@') {
          j = i - 1
          maskedEmail[i] = email[j] + email[i] + email[i + 1]
        }
        previous = email[i]
      }
      return maskedEmail.join('')
    }

// Usage:
//	console.log ( emailMask("[email protected]") );
// Output: my.e***l@m*******.c**