sierra-record-check-digit

Calculates the check digit for a Sierra record number.

Install

npm install '@sydneyunilibrary/sierra-record-check-digit'

How to use

In NodeJS v8+:

const { addCheckDigit, calcCheckDigit } = require('@sydneyunilibrary/sierra-record-check-digit')

In ECMAScript 2015+:

import { addCheckDigit, calcCheckDigit } from '@sydneyunilibrary/sierra-record-check-digit'

calcCheckDigit

calcCheckDigit calculates a check digit for a given record number. The given record number can be a string or a number. Regardless, the returned check digit will be a string.

calcCheckDigit('3384632') // => '7'
calcCheckDigit(3384632) // => '7'
calcCheckDigit(1125421) // => 'x'

The record number must be just the number part. It cannot include a record type char, an initial period or the virtual record part. calcCheckDigit will throw an error if it does.

calcCheckDigit('i4105199') // => throws Error
calcCheckDigit('.i4105199') // => throws Error
calcCheckDigit('i4105199@abcde') // => throws Error

calcCheckDigit presumes the given record number does not have a check digit. calcCheckDigit will give the wrong result if you give it a record number that does have a check digit.

addCheckDigit

addCheckDigit calculates the check digit for a given record number and returns a new string that includes both the record number and the check digit. The given record number can be a string or number. It can include a record type char and an initial period.

addCheckDigit(3384632) // => '33846327'
addCheckDigit('3384632') // => '33846327'
addCheckDigit('i3384632') // => 'i33846327'
addCheckDigit('.i3384632') // => '.i33846327'

You can explicitly give addCheckDigit a check digit to add. You can do this if you want to add the palceholder check digit a, or if you already know the check digit want to save addCheckDigit for having to calculate it. addCheckDigit will not validate the check digit you give it in any way.

addCheckDigit('3384632', { checkDigit: 'a' }) // => '3384632a'
addCheckDigit('i3384632', { checkDigit: '7' }) // => 'i33846327'
addCheckDigit('i3384632', { checkDigit: '!' }) // => 'i3384632!'

addCheckDigit will not add a check digit to a virtual record number by default, even if you explicitly give it a check digit to add. This mirrors Sierra's own behaviour.

addCheckDigit('i3384632@abcd') // => 'i3384632@abcd'
addCheckDigit('.i3384632@abcd') // => '.i3384632@abcd'

You can include an option to force addCheckDigit to add a check digit to virtual record numbers.

addCheckDigit('i3384632@abcd', { addToVirtualRecords: true}) // => 'i33846327@abcd'
addCheckDigit('.i3384632@abcd', { addToVirtualRecords: true}) // => '.i33846327@abcd'

addCheckDigit presumes the given record number does not already include the check digit. If you give it a record number that does include a check digit, addCheckDigit will add another check digit and you will end up with an invalid record number. If you don't know if a record number has a check digit, you can use the detect function from @SydneyUniLibrary/sierra-record-id to find out.

License

Copyright (c) 2017 The University of Sydney Library

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.