makeIndex.js

import { existsSync, readdirSync, readFileSync, writeFileSync } from "fs";
import ignore from "ignore";
import minimist from "minimist";
import { basename, extname, join, relative } from "path";
import { fileURLToPath } from "url";

const MODULE_ENDING_SPECIFIER = ".js";
const QUOTE_CHAR = '"';

const opts = minimist(process.argv.slice(2));
const dirs = opts._.length ? opts._ : [process.cwd()];
const depth = opts.depth && parseInt(opts.depth, 10);

const defaultIgnore = ignore().add([
  "internal/",
  "*.internal.*",
  "*.test.ts",
  "*.d.ts",
  "__test__/",
]);

dirs.forEach((x) => makeIndex(x, depth, opts.comment));

function makeIndex(dir, maxDepth, comment) {
  const files = collectFiles(dir, { maxDepth })
    .map((x) => relative(dir, x).replace("\\", "/"))
    .filter((x) => x !== getImportPath("./", "index"))
    .sort(sortPath);

  if (!comment) {
    comment = `node ${relative(dir, fileURLToPath(import.meta.url))}`;
  }

  const index = [`// AUTO-GENERATED ${comment}`].concat(
    files.map((x) => `export * from ${QUOTE_CHAR}./${x}${QUOTE_CHAR};`)
  );

  const output = index.join("\n") + "\n";
  const outputFile = join(dir, "index.ts");

  if (opts.ci) {
    if (readFileSync(outputFile, "utf8") !== output) {
      console.log(`ERROR: ${outputFile} would change`);
      process.exit(1);
    }
  } else {
    writeFileSync(outputFile, output);
  }
}

function collectFiles(
  dir,
  { currentDepth = 0, ignoreFiles = defaultIgnore, maxDepth = 5, rootDir = dir }
) {
  const ignorePath = join(dir, ".indexignore");
  if (existsSync(ignorePath)) {
    ignoreFiles = ignore()
      .add(ignoreFiles)
      .add(readFileSync(ignorePath, "utf8"));
  }
  let files = readdirSync(dir, { withFileTypes: true });
  const matches = [];

  if (currentDepth > 0 && files.find((x) => x.name === "index.ts")) {
    return [dir];
  }

  for (const file of files) {
    const relPath = getIgnorePath(dir, file, rootDir);
    if (ignoreFiles && ignoreFiles.ignores(relPath)) {
      continue;
    }
    if (file.isDirectory() && currentDepth <= maxDepth) {
      matches.push(
        ...collectFiles(join(dir, file.name), {
          currentDepth: currentDepth + 1,
          ignoreFiles,
          maxDepth,
          rootDir,
        })
      );
    } else if (shouldIndexFile(file.name)) {
      matches.push(getImportPath(dir, file.name));
    }
  }

  return matches;
}

function getImportPath(basePath, path) {
  return join(
    basePath,
    basename(path, extname(path)) + MODULE_ENDING_SPECIFIER
  );
}

function shouldIndexFile(name) {
  return /\.tsx?$/.test(name);
}

function getIgnorePath(dir, file, rootDir) {
  let filePath = relative(rootDir, join(dir, file.name));
  if (file.isDirectory()) {
    filePath += "/";
  }
  return filePath;
}

function sortPath(a, b) {
  return a.toLowerCase().localeCompare(b.toLowerCase());
}