stdnum/src/gen/ean.ts

Standard Number Validation

/**
 * EAN (International Article Number).
 *
 * This handles numbers EAN-13, EAN-8, UPC (12-digit)
 * and GTIN (EAN-14) format.
 */

import * as exceptions from '../exceptions';
import * as strings from '../util/strings';
import { Validator, ValidateReturn } from '../types';
import { weightedSum } from '../util/checksum';

function clean(input: string): ReturnType<typeof strings.cleanUnicode> {
  return strings.cleanUnicode(input, ' -');
}

const impl: Validator = {
  name: 'International Article Number',
  localName: 'International Article Number',
  abbreviation: 'EAN',
  compact(input: string): string {
    const [value, err] = clean(input);

    if (err) {
      throw err;
    }

    return value;
  },

  format(input: string): string {
    const [value] = clean(input);

    return value;
  },

  validate(input: string): ValidateReturn {
    const [value, error] = clean(input);

    if (error) {
      return { isValid: false, error };
    }
    if (![8, 12, 13, 14].includes(value.length)) {
      return { isValid: false, error: new exceptions.InvalidLength() };
    }
    if (!strings.isdigits(value)) {
      return { isValid: false, error: new exceptions.InvalidFormat() };
    }

    const [front, check] = strings.splitAt(value, -1);
    const sum = weightedSum(front, {
      modulus: 10,
      weights: [3, 1],
      reverse: true,
    });

    if (String((10 - sum) % 10) !== check) {
      return { isValid: false, error: new exceptions.InvalidChecksum() };
    }

    return {
      isValid: true,
      compact: value,
      isIndividual: false,
      isCompany: false,
    };
  },
};

export const { name, localName, abbreviation, validate, format, compact } =
  impl;