mapDirContents.ts

type MapDirContentsOptions = {
  dirPath: string;
  pattern: string;
};
const mapDirContents = ({
  dirPath,
  pattern,
}: MapDirContentsOptions): Map<string, string> => {
  const fileNames = glob.sync(path.join(dirPath, pattern), {
    dot: true,
    nodir: true,
  });
  fileNames.sort((a, b) => a.localeCompare(b));
  return new Map(
    fileNames.map((fileName) => [
      path.relative(dirPath, fileName),
      fs.readFileSync(fileName).toString(),
    ]),
  );
};

describe("mapDirContents", () => {
  let tmpDir: DirResult;
  beforeAll(() => {
    tmpDir = tmp.dirSync({ unsafeCleanup: true });
  });
  afterAll(() => {
    tmpDir.removeCallback();
  });

  const writeFile = (relPath: string, contents: string) => {
    const filePath = path.join(tmpDir.name, relPath);
    mkdirp.sync(path.parse(filePath).dir);
    fs.writeFileSync(filePath, contents);
  };

  it("should produce expected content", () => {
    const data = new Map([
      [".env", "HELLO=WORLD"],
      ["package.json", JSON.stringify({ name: "mypkg" })],
      ["src/index.ts", 'export const PACKAGE_NAME = "mypkg";'],
    ]);
    Array.from(data).forEach(([fileName, contents]) =>
      writeFile(fileName, contents),
    );

    const result = mapDirContents({ dirPath: tmpDir.name, pattern: "**" });
    expect(result).toEqual(data);
  });
});