Convert a DOI or DOI URL to JSON via CrossRef API

doi2json.ts

/**
 * Gets JSON citation data from the CrossRef API for a DOI or DOI URL
 * @param doiOrUrl A DOI or DOI URL
 */
export async function doi2json(doiOrUrl: string) {
  // Extract the DOI from the URL or use it directly if it's not a URL
  const doi = doiOrUrl.replace(/^https?:\/\/doi\.org\//, '');

  // Fetch data from the CrossRef API
  const response = await fetch(`https://api.crossref.org/works/${doi}`);
  if (!response.ok) {
    throw new Error(`HTTP error! status: ${response.status}`);
  }
  const { message } = await response.json();
  
  // Strip out the references, which are huge and not needed
  const { reference, ...info } = message;

  // If there are more than 20 authors, help the LLM pull the list apart
  if (info.author.length > 20) {
    const modifiedAuthors = info.author.map((author, idx) => {
      const isRequiredInCitation = idx === info.author.length - 1 || idx < 20;
      return {
        // Let the LLM know which author this is in the set of authors
        authorNumber: idx + 1,
        // Give a clue about the need to include/exclude this author
        isAuthorRequiredInCitation,
        ...author
      };
    });
    
    return {
      ...info,
      // Count the authors for the LLM
      authorCount: info.author.length,
      // Provide additional instuctions hint about how to do the authors list in this case
      apaCitationInstructions: "Remember to include ALL of the first 19 authors along with the final author",
      author: modifiedAuthors
    };
  }

  return {
    authorCount: info.author.length,
    ...info,
  };
}