gatsby-plugin-prefetch-google-fonts/download-fonts.js

A Gatsby plugin to download and prefetch [Google Fonts](https://fonts.google.com/). Can increase performance as opposed to loading webfonts from Google's external stylesheet.

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

var _regenerator = _interopRequireDefault(require("@babel/runtime/regenerator"));

var _toConsumableArray2 = _interopRequireDefault(require("@babel/runtime/helpers/toConsumableArray"));

var _asyncToGenerator2 = _interopRequireDefault(require("@babel/runtime/helpers/asyncToGenerator"));

var _require = require("fs-extra"),
    readFile = _require.readFile,
    pathExists = _require.pathExists,
    ensureDir = _require.ensureDir,
    outputFile = _require.outputFile;

var _require2 = require("url"),
    parse = _require2.parse;

var getUrls = require("get-urls");

var download = require("download");

var path = require("path");

module.exports =
/*#__PURE__*/
function () {
  var _ref = (0, _asyncToGenerator2.default)(
  /*#__PURE__*/
  _regenerator.default.mark(function _callee(config) {
    var cachedPath, filePath, cssData, fontLinks, domains, fontPaths, i, url, _parse, pathname, protocol, hostname, origin, dirPath, rootPath;

    return _regenerator.default.wrap(function _callee$(_context) {
      while (1) {
        switch (_context.prev = _context.next) {
          case 0:
            cachedPath = path.join("./.cache/google-fonts/", config.pathPrefix);
            filePath = path.join(cachedPath, "google-fonts.css"); // Extract URLs from CSS

            _context.next = 4;
            return readFile(filePath, "utf8");

          case 4:
            cssData = _context.sent;
            fontLinks = (0, _toConsumableArray2.default)(getUrls(cssData)); // Download font files

            domains = [];
            fontPaths = [];
            i = fontLinks.length;

          case 9:
            if (!i--) {
              _context.next = 28;
              break;
            }

            url = fontLinks[i].split(")")[0];
            _parse = parse(url), pathname = _parse.pathname, protocol = _parse.protocol, hostname = _parse.hostname;
            origin = "".concat(protocol, "//").concat(hostname);

            if (domains.indexOf(origin) === -1) {
              domains.push(origin);
            }

            if (fontPaths.indexOf(pathname) === -1) {
              fontPaths.push(pathname);
            }

            _context.next = 17;
            return pathExists("".concat(cachedPath, "/fonts").concat(pathname));

          case 17:
            if (_context.sent) {
              _context.next = 26;
              break;
            }

            dirPath = pathname.split(/[\/\\]/);
            dirPath.pop();
            dirPath = dirPath.join("/");
            dirPath = "".concat(cachedPath, "/fonts").concat(dirPath);
            _context.next = 24;
            return ensureDir(dirPath);

          case 24:
            _context.next = 26;
            return download(url, dirPath);

          case 26:
            _context.next = 9;
            break;

          case 28:
            rootPath = "".concat(config.pathPrefix.replace(/\/$/, ""), "/google-fonts"); // Replace domains with relative paths in CSS

            domains.forEach(function (domain) {
              while (cssData.indexOf(domain) !== -1) {
                cssData = cssData.replace(domain, rootPath).replace(/\\/g, "/");
              }
            });
            _context.next = 32;
            return outputFile(filePath, cssData);

          case 32:
          case "end":
            return _context.stop();
        }
      }
    }, _callee, this);
  }));

  return function (_x) {
    return _ref.apply(this, arguments);
  };
}();