swiss-ssn/src/swiss-ssn.js

Small utility for validating and generating Swiss national identification number.

"use strict"
/**
 * Project: swiss-ssn
 * Purpose: Validate and generate Swiss SSN's according to http://www.sozialversicherungsnummer.ch/aufbau-neu.htm
 * Author:  teaddict
 * @version 1.0.2
 */

class SwissSSN {
  static #COUNTRY_CODE = [7, 5, 6]
  static #MAX_VALUE = 10
  static #SSN_LENGTH = 13

  /**
   * Validates parameter given SSN. Returns true if SSN is valid, otherwise false.
   * @param {string} ssn - For example '756.9217.0769.85' or '7569217076985'
   * @returns {boolean}
   */
  static validateSSN(ssn) {
    if (!ssn) {
      return false
    }

    const parsedSSN = this.#parse(ssn)
    if (parsedSSN.length !== this.#SSN_LENGTH) {
      return false
    }

    const checkDigit = this.#getCheckDigit(parsedSSN)
    return parseInt(parsedSSN[12], 10) === checkDigit
  }

  /**
   * Creates a valid SSN using random numbers.
   * @returns {string} - valid ssn.
   */
  static generateSSN() {
    const randomNumbers = Array.from(
      { length: 9 }, 
      () => Math.floor(Math.random() * this.#MAX_VALUE)
    )
    
    const ssnWithoutCheckDigit = [...this.#COUNTRY_CODE, ...randomNumbers]
    const checkDigit = this.#getCheckDigit(ssnWithoutCheckDigit)
    const unformattedSSN = [...ssnWithoutCheckDigit, checkDigit]
    
    return this.#ssnFormatter(unformattedSSN)
  }

  /**
   * Calculate check digit for SSN
   * @private
   */
  static #getCheckDigit(ssn) {
    const total = [...ssn]
      .slice(0, 12)
      .reduce((sum, digit, index) => {
        const multiplier = index % 2 === 0 ? 1 : 3
        return sum + (parseInt(digit, 10) * multiplier)
      }, 0)

    return total % 10 === 0 ? 0 : (Math.ceil(total / 10) * 10) - total
  }

  /**
   * Format SSN with dots
   * @private
   */
  static #ssnFormatter(ssn) {
    const ssnString = ssn.map(String)
    return `756.${ssnString.slice(3, 7).join("")}.${ssnString.slice(7, 11).join("")}.${ssnString.slice(11, 13).join("")}`
  }

  /**
   * Parse SSN string by removing all non-digit characters
   * @private
   */
  static #parse(ssn) {
    return ssn.replace(/\D/g, "")
  }
}

// Export for different environments
if (typeof window !== "undefined") {
  window.SwissSSN = SwissSSN // Browser global
}

export default SwissSSN