id

@allmaps/id

Uses the SHA-1 algorithm to generate IDs from strings, random IDs from UUIDs and checksums from JSON objects.

Allmaps uses this module to create IDs from IIIF URIs. For example:

• Given the following manifest URL: https://polona.pl/iiif/item/NTU5NTE4OTg/manifest.json,
• The output of the generateId function will be: 4ac2770ae8624e38,
• We can use this ID to view the annotation for the georeferenced maps in the manifest in Allmaps: https://dev.annotations.allmaps.org/manifests/4ac2770ae8624e38.

To see @allmaps/id in action, view this Observable notebook.

Usage

This is an ESM-only module that works in browsers or in Node.js.

Node.js:

The Node.js version of @allmaps/id usescrypto.createHash() and crypto.randomUUID() from the crypto module. First, run npm install @allmaps/id.

import { generateId } from '@allmaps/id'
const url =
  'https://orka.bibliothek.uni-kassel.de/viewer/rest/iiif/manifests/1535113582549/manifest/'
const id = await generateId(url)
console.log(id)

Browser:

The browser version of @allmaps/id uses the SubtleCrypto.digest() and Crypto.randomUUID() Web APIs.

<script type="module">
  import { generateId } from 'https://unpkg.com/@allmaps/id?module'

  const url =
    'https://orka.bibliothek.uni-kassel.de/viewer/rest/iiif/manifests/1535113582549/manifest/'
  const id = await generateId(url)
  console.log(id)
</script>

API

Table of Contents

• generateId
  • Parameters
• generateRandomId
  • Parameters
• generateChecksum
  • Parameters

generateId

Generates an ID from a string using the SHA-1 algorithm. Given the same input, the ID will always be the same.

Parameters

• str string Input string.
• length number Length of returned hash. The maximum length of the hash is 40 characters. (optional, default 16)

Returns string First length characters of the SHA-1 hash of str.

generateRandomId

Generates a random ID.

Parameters

• length number Length of returned hash. The maximum length of the hash is 40 characters. (optional, default 16)

Returns string First length characters of the SHA-1 hash of a random UUID.

generateChecksum

Generates a checksum of a JSON object.

Parameters

• obj Object JSON object.
• length number Length of returned hash. The maximum length of the hash is 40 characters. (optional, default 16)

Returns string First length characters of the SHA-1 hash of sorted and serialized version of obj.