routing-validator/dist/routing-validator.es5.js

Validates the MICR format of an ABA routing number.

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;
}();

export default RoutingValidator;