routing-validator/dist/routing-validator.umd.js

Validates the MICR format of an ABA routing number.

(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
  typeof define === 'function' && define.amd ? define(factory) :
  (global.routingValidator = factory());
}(this, (function () { 'use strict';

  function checksum(number) {
    if (number && typeof number === 'string' && /^\d{8}$/.test(number)) {
      var weights = [3, 7, 1];
      var weighedSum = number.split('').reduce(function (previous, current, i) {
        return previous + weights[i % 3] * parseInt(current, 10);
      }, 0);

      var checkdigit = (10 - weighedSum % 10) % 10;
      return checkdigit.toString();
    }
    return number;
  }

  var classCallCheck = function (instance, Constructor) {
    if (!(instance instanceof Constructor)) {
      throw new TypeError("Cannot call a class as a function");
    }
  };

  var createClass = function () {
    function defineProperties(target, props) {
      for (var i = 0; i < props.length; i++) {
        var descriptor = props[i];
        descriptor.enumerable = descriptor.enumerable || false;
        descriptor.configurable = true;
        if ("value" in descriptor) descriptor.writable = true;
        Object.defineProperty(target, descriptor.key, descriptor);
      }
    }

    return function (Constructor, protoProps, staticProps) {
      if (protoProps) defineProperties(Constructor.prototype, protoProps);
      if (staticProps) defineProperties(Constructor, staticProps);
      return Constructor;
    };
  }();

  var RoutingValidator = function () {
    function RoutingValidator(routingNumber) {
      classCallCheck(this, RoutingValidator);

      this.number = routingNumber && routingNumber.toString();
    }

    createClass(RoutingValidator, [{
      key: 'isValid',
      value: function isValid() {
        if (!this.number) {
          throw 'was not constructed with a number';
        }

        if (!/^\d{9}$/.test(this.number)) {
          this.error = 'Routing Number must be exactly 9 numbers';
          return false;
        }

        var firstEight = this.number.substring(0, 8);
        var lastOne = this.number.substring(8, 9);
        var checkdigit = checksum(firstEight);

        if (checkdigit !== lastOne) {
          this.error = 'Routing Number is invalid';
          return false;
        }

        this.error = '';
        return true;
      }
    }, {
      key: 'errorMessage',
      value: function errorMessage() {
        if (this.error == null) {
          this.isValid();
        }
        return this.error;
      }
    }, {
      key: 'routingNumber',
      get: function get$$1() {
        return this.number;
      },
      set: function set$$1(routingNumber) {
        this.number = routingNumber;
      }
    }]);
    return RoutingValidator;
  }();

  return RoutingValidator;

})));