Parse Github `Links` header in JavaScript

gistfile1.js

/*
 * parse_link_header()
 *
 * Parse the Github Link HTTP header used for pageination
 * http://developer.github.com/v3/#pagination
 */
function parse_link_header(header) {
  if (header.length == 0) {
    throw new Error("input must not be of zero length");
  }

  // Split parts by comma
  var parts = header.split(',');
  var links = {};
  // Parse each part into a named link
  _.each(parts, function(p) {
    var section = p.split(';');
    if (section.length != 2) {
      throw new Error("section could not be split on ';'");
    }
    var url = section[0].replace(/<(.*)>/, '$1').trim();
    var name = section[1].replace(/rel="(.*)"/, '$1').trim();
    links[name] = url;
  });

  return links;
}

Handle the comma inside quotes with lookahead/lookbehind (only works on JS engines that support it)

function parseLinkHeader(header) {
    if (header.length === 0) {
        throw new Error("input must not be of zero length");
    }

    // Split parts by comma and parse each part into a named link
    return header.split(/(?!\B"[^"]*),(?![^"]*"\B)/).reduce((links, part) => {
        const section = part.split(/(?!\B"[^"]*);(?![^"]*"\B)/);
        if (section.length < 2) {
            throw new Error("section could not be split on ';'");
        }
        const url = section[0].replace(/<(.*)>/, '$1').trim();
        const name = section[1].replace(/rel="(.*)"/, '$1').trim();

        links[name] = url;

        return links;
    }, {});
}

Can't it be as simple as?

function parseLink(s) {
  const output = {};
  const regex = /<([^>]+)>; rel="([^"]+)"/g;

  let m;
  while (m = regex.exec(s)) {
    const [_, v, k] = m;
    output[k] = v;
  }

  return output;
}

Usage: parseLink(headers.get("link"))

There is a package for this github-parse-link

Lodash:

const links = _.chain(link)
        .split(',')
        .map(link => {
          return {
            ref: link.split(';')[1].replace(/rel="(.*)"/, '$1').trim(),
            url: link.split(';')[0].replace(/<(.*)>/, '$1').trim(),
          }
        })
        .keyBy('ref')
        .mapValues('url')
        .value()