terriajs-typings-for-css-modules-loader/src/verify.js

Webpack loader that generates TypeScript typings for CSS modules from css-loader on the fly

// @ts-check
const fs = require("fs");
const util = require("util");
const fsStat = util.promisify(fs.stat);
const fsReadFile = util.promisify(fs.readFile);
/**
 * @param {string} filename
 * @param {string} content
 * @returns {Promise<void>}
 */
module.exports = async (filename, content) => {
  const fileExists = await fsStat(filename)
    .then(() => true)
    .catch(() => false);

  if (!fileExists) {
    throw new Error(
      `Verification failed: Generated typings for css-module file '${filename}' is not found. ` +
        "It typically happens when the generated typings were not committed."
    );
  }

  const existingFileContent = await fsReadFile(filename, "utf-8");

  // let's not fail the build if there are whitespace changes only
  if (existingFileContent.replace(/\s+/g, "") !== content.replace(/\s+/g, "")) {
    throw new Error(
      `Verification failed: Generated typings for css-modules file '${filename}' is out of date. ` +
        "It typically happens when the up-to-date generated typings are not committed."
    );
  }
};