lint-staged.config.js

const path = require('path');

const FRONTEND_DIR = 'FrontEnd/my-app';
const BACKEND_DIR = 'BackEnd';

function buildCommands(cwd, command, files) {
  if (files.length === 0) {
    return [];
  }

  // Use --prefix instead of changing directories to be compatible with
  // Windows/git-hook environments where `cd` may fail.
  // Note: npx --prefix does NOT change the working directory, so we must
  // pass the absolute paths (or paths relative to root) to the command.
  const escapedFiles = files.map((file) => `"${file.replace(/\\/g, '/')}"`);
  return [`npx --prefix ${cwd} ${command} ${escapedFiles.join(' ')}`];
}

function buildNpmScript(cwd, scriptName, files) {
  const relativeFiles = files.map((file) => path.relative(cwd, file).replace(/\\/g, '/'));
  if (relativeFiles.length === 0) return [];
  return [`npm --prefix ${cwd} run ${scriptName} -- --fix ${relativeFiles.join(' ')}`];
}

/** @type {import('lint-staged').Configuration} */
module.exports = {
  'FrontEnd/my-app/**/*.{js,jsx,ts,tsx,css,scss,md,json,yml,yaml}': (files) => [
    ...buildCommands(FRONTEND_DIR, 'prettier --write', files),
    ...buildNpmScript(FRONTEND_DIR, 'lint', files),
  ],
  'BackEnd/{src,test}/**/*.ts': (files) => [
    ...buildCommands(BACKEND_DIR, 'prettier --write', files),
    ...buildNpmScript(BACKEND_DIR, 'lint', files),
  ],
  'BackEnd/**/*.json': (files) =>
    buildCommands(BACKEND_DIR, 'prettier --write', files),
  '{scripts,tests}/**/*.{js,mjs,cjs,json,md,yml,yaml}': (files) => [
    `npx prettier --write ${files.map((file) => file.replace(/\\/g, '/')).join(' ')}`,
  ],
};