gatsby-plugin-workerize-loader/gatsby-ssr.js

Integrate workerize-loader with GatsbyJS

"use strict";

const React = require('react');

const {
  readdirSync
} = require('fs');

const {
  PREFIX
} = require('./constants');

const publicFolder = './public';

const isWorker = file => file.includes(PREFIX) && file.endsWith('.worker.js');

const shouldPreload = (file, preloads) => file.startsWith(PREFIX) && preloads.some(preload => file.includes(preload));

let preloadScripts = []; // For some reason, this does not work as expected on Chrome.
// So for now, I'm not mentioning preloads option in README.
//
// Be aware that adding preloads will prevent Gatsby to use the `GATSBY_EXPERIMENTAL_PAGE_BUILD_ON_DATA_CHANGES` flag

exports.onRenderBody = ({
  setHeadComponents
}, {
  preloads = []
} = {}) => {
  if (!preloads.length) return;

  if (!preloadScripts.length) {
    preloadScripts = readdirSync(publicFolder).filter(file => isWorker(file) && shouldPreload(file, preloads)).map(file => /*#__PURE__*/React.createElement("link", {
      key: file,
      as: "worker",
      crossOrigin: "anonymous",
      href: `/${file}`,
      rel: "preload"
    }));
  }

  setHeadComponents(preloadScripts);
};