import-essex/cache.js

Import JSX as essex components in NodeJS

// Based on https://github.com/babel/babel-loader/blob/15df92fafd58ec53ba88efa22de7b2cee5e65fcc/src/cache.js
import { readFileSync } from 'node:fs';
import fsp from 'node:fs/promises';
import os from 'node:os';
import path from 'node:path';
import crypto from 'node:crypto';
import { makeDirectory } from 'make-dir';
import findCacheDir from 'find-cache-directory';

const __filename = (new URL(import.meta.url)).pathname;
const __dirname = path.dirname(__filename);

const cacheDirectory = findCacheDir({ name: 'import-essex' }) || os.tmpdir();
const packageConfig = JSON.parse(readFileSync(path.resolve(__dirname, 'package.json'), 'utf8'));

export const cacheKeyFromSource = (source) => {
  const contents = JSON.stringify({
    source,
    version: packageConfig.version,
  });

  return `${crypto.createHash('md5').update(contents).digest('hex')}.js`;
};

const cachedTransform = async (
  transform,
  parameters,
  directory = cacheDirectory
) => {
  const { enabled, key } = parameters;

  if (!enabled) {
    return transform();
  }

  const file = path.join(directory, key);

  try {
    // No errors mean that the file was previously cached
    // we just need to return it
    return await fsp.readFile(file, 'utf8');
  } catch (e) {
    // do nothing
  }

  const fallback = directory !== os.tmpdir();

  // Make sure the directory exists.
  try {
    await makeDirectory(directory);
  } catch (error) {
    if (fallback) {
      return cachedTransform(transform, parameters, os.tmpdir());
    }

    throw error;
  }

  // Otherwise just transform the file
  // return it to the user asap and write it in cache
  const result = await transform();

  try {
    await fsp.writeFile(file, result);
  } catch (error) {
    if (fallback) {
      // Fallback to tmpdir if node_modules folder not writable
      return cachedTransform(transform, parameters, os.tmpdir());
    }

    throw error;
  }

  return result;
};

export default cachedTransform;