@altmetric/identifiers

Extract scholarly identifiers from text strings. Supports Node.js 18, 20, and 22.

Supported Identifiers

• DOI - Digital Object Identifiers (including ISBN-As)
• arXiv - arXiv preprint identifiers (pre-2007 and post-2007 formats)
• ORCID - Open Researcher and Contributor IDs (with checksum validation)
• PubMed - PubMed identifiers
• Bibcode - ADS Bibliographic Codes
• Handle - Handle System identifiers
• NCT - National Clinical Trial identifiers
• RePEc - Research Papers in Economics identifiers
• URN - Uniform Resource Names

Installation

npm install @altmetric/identifiers

Usage

Import individual identifiers (recommended for tree-shaking)

import { extract } from "@altmetric/identifiers/doi";

extract("This is a DOI: 10.1234/foo.bar");
//=> ["10.1234/foo.bar"]

Import multiple identifiers

import { extract as extractDoi } from "@altmetric/identifiers/doi";
import { extract as extractArxiv } from "@altmetric/identifiers/arxiv";

extractDoi("10.1234/foo.bar");
//=> ["10.1234/foo.bar"]

extractArxiv("arXiv:1501.00001v2");
//=> ["1501.00001v2"]

Import all identifiers

import * as identifiers from "@altmetric/identifiers";

identifiers.doi.extract("10.1234/foo.bar");
//=> ["10.1234/foo.bar"]

identifiers.arxiv.extract("math.GT/0309136");
//=> ["math.GT/0309136"]

identifiers.orcid.extract("0000-0002-0488-8591");
//=> ["0000-0002-0488-8591"]

URN special case

The URN module exports both extract() (normalized) and scan() (raw):

import { extract, scan } from "@altmetric/identifiers/urn";

scan("URN:FOO:BAR");
//=> ["URN:FOO:BAR"]

extract("URN:FOO:BAR");
//=> ["urn:foo:BAR"]

TypeScript

Type definitions are included for all modules.

import { extract } from "@altmetric/identifiers/doi";

const dois: string[] = extract("10.1234/foo");

Migration from individual packages

This package replaces the following individual packages:

Old package	New import
identifiers-arxiv	@altmetric/identifiers/arxiv
identifiers-bibcode	@altmetric/identifiers/bibcode
identifiers-doi	@altmetric/identifiers/doi
identifiers-handle	@altmetric/identifiers/handle
identifiers-nct	@altmetric/identifiers/nct
identifiers-orcid	@altmetric/identifiers/orcid
identifiers-pubmed	@altmetric/identifiers/pubmed
identifiers-repec	@altmetric/identifiers/repec
identifiers-urn	@altmetric/identifiers/urn

The API is the same — every module exports an extract() function (URN also exports scan()). The only change is the import path and switching from CommonJS require() to ES module import:

// Before (CommonJS)
const doi = require("identifiers-doi");
doi.extract("10.1234/foo");

// After (ES modules)
import { extract } from "@altmetric/identifiers/doi";
extract("10.1234/foo");

Other versions

We also maintain versions of these libraries for Ruby and PHP.

License

Copyright © 2017-2026 Altmetric LLP

Distributed under the MIT License.