next.config.js

// @ts-check

// This file is the main configuration of the MathHub nextjs app. 
// It's read only once, and directly from within node. 
// For this reason we can't use "import" statements, as node doesn't natively support them.

const { resolve } = require("path");
const { ProvidePlugin } = require("webpack");
const gitRevSync = require("git-rev-sync");

const localeManifest = require("./src/locales/data/manifest.json");


/** @type{import("./src/types/config").IMathHubConfig} */
const config = {
  "MATHHUB_VERSION": mathhubversion(),

  // read the rest of the environment variables from the real environment
  // TODO: Consider moving these directly into NEXT_PUBLIC_ so that they're easier to setup
  ...readenv([
    "LIBRARY_URL",
    "NEWS_URL",
    "GLOSSARY_URL",
    "TRANSLATION_URL",
    "ADMIN_URL",
    "UPSTREAM_BASE_URL",
  ])
}

module.exports = {
  i18n: {
    locales: localeManifest,
    defaultLocale: localeManifest[0],
  },

  poweredByHeader: false,
  webpack,
  env: {MATHHUB_CONFIG: config},
};

/**
 * webpack updates the webpack configuration
 * @param {import("webpack").Configuration} config 
 * @param {*} options 
 * @return {import("webpack").Configuration}
 */
function webpack(config, options) {
  // when we are not on the server, we need to provide jquery
  if (!options.isServer) {
    config.plugins.push(new ProvidePlugin({ "$": "jQuery", "jQuery": "jquery" }));
  }

  return config;
}

/**
 * Build version information about this version of MathHub. 
 * 
 * @returns {import("./src/types/config").IMathHubVersion}
 */
function mathhubversion() {
  const pkg = require("./package.json").version; // TODO: Use readfile

  const root = resolve(__dirname, "..");

  /** @type {import("./src/types/config").IMathHubVersion["git"] | undefined} */
  let git = undefined;

  try {
    const gitHash = gitRevSync.long(root);
    if (!gitHash) {
      throw new Error("no git hash");
    }

    git = { hash: gitHash };

    try {
      const branch = gitRevSync.branch(root);
      git.branch = branch ? (branch + "") : undefined;
    } catch (f) { }

    try {
      git.dirty = gitRevSync.isDirty();
    } catch (f) { }

    try {
      git.time = gitRevSync.date().getTime();
    } catch (f) { }
  } catch (e) { }

  return {
    semantic: pkg,
    configTime: new Date().getTime(),
    git: git,
  };
}

/**
 * Readenv reads variables from the environment and returns a dictionary containing them. 
 * 
 * @param {string[]} variables
 * @return {Object.<string, string>}
 */
function readenv(variables) {
  /** @type Object.<string, string> */
  const dict = {};
  variables.forEach(v => dict[v] = process.env[v] || undefined);
  return dict;
}