index.js

'use strict';

const { URL } = require('url');

const URL_PATTERNS = new RegExp(/^\/?:?([/\w-.]+)\/([\w-.]+)\/?$/);
const GITHUB_API = new RegExp(/^\/repos\/([\w-.]+)\/([\w-.]+)\/(?:tarball|zipball)(?:\/.+)?$/);
const GITHUB_CODELOAD = new RegExp(/^\/([\w-.]+)\/([\w-.]+)\/(?:legacy\.(?:zip|tar\.gz))(?:\/.+)?$/);

module.exports = url => {
  const modifiedURL = url
    // Prepend `https` to the URL so that `url.URL` will see the value of `url` as an actual `url`, and therefore, correctly parse it.
    .replace(/^git@/, 'https://git@')

    // Replace `:` with `/` before path segments so that `url.URL` will see the value of `url` as an actual `url`, and therefore, correctly parse it.
    .replace(/git@([.\w]+):(?!\d)/, 'git@$1/')

    // Remove `.git` from any URL before applying regular expressions to the string. Removing `.git` through a non capture group is kind of difficult.
    .replace(/\.git$/, '');

  const parsedURL = new URL(modifiedURL, 'https://example.com/');
  const format = matches => {
    return { browse: createBrowseURL(parsedURL, matches), domain: parsedURL.host, project: matches[2] || null, type: getType(parsedURL), user: matches[1] || null };
  };

  if (parsedURL.host) {
    if (parsedURL.host.includes('api.github.com')) {
      const matches = GITHUB_API.exec(parsedURL.pathname) || [];
      return format(matches);
    }

    if (parsedURL.host.includes('codeload.github.com')) {
      const matches = GITHUB_CODELOAD.exec(parsedURL.pathname) || [];
      return format(matches);
    }
  }

  return format(URL_PATTERNS.exec(parsedURL.pathname) || []);
};

function getType ({ host }) {
  if (typeof host !== 'string') {
    return null;
  }

  if (host.indexOf('github') !== -1) {
    return 'github';
  }
  if (host.indexOf('gitlab') !== -1) {
    return 'gitlab';
  }

  return null;
}

function createBrowseURL (parsedURL, matches) {
  const protocol = parsedURL.protocol === 'http:' ? 'http:' : 'https:';
  const browseURL = `${protocol}//${parsedURL.host}/${matches[1]}/${matches[2]}`;

  return () => {
    return browseURL;
  };
}