babel build without bundling

.babelrc

{
  "presets": [
    "stage-1",
    [
      "env", {
        "targets": {
          "browsers": ["Chrome >= 61"],
          "node": 6
        },
        "modules": "commonjs"
      }
    ],
    "react"
  ],
  "plugins": [
    [
      "css-modules-transform",{
        "preprocessCss": "./preprocess-scss.js",
        "extractCss": "./dev_build/style-bundle.css",
        "extensions": [
          ".css",
          ".scss"
        ]
      }
    ]
  ],
  "sourceMaps": true
}

node-walk.js

const fs = require('fs');
const path = require('path');
const mkdirp = require('mkdirp');
const minimatch = require('minimatch');
const babel = require('babel-core');

// TODO: instead of working on paths, try to resolve dependencies
const EXTNAMES = ['.js', '.jsx', '.mjs'];
const INCLUDE_FILES = ['src/'];
const EXCLUDE_FILES = [
  '**/setupTests.js',
  '**/*.test.js'
];
const OUT_DIR = 'dev_build/';
const BABEL_OPTIONS = {

};

console.time('build');

process.on('exit', (code) => {
  console.timeEnd('build');
});

// TODO: support walk('path', () => {})
function walk(filePath, options = {}, callback) {
  // if (!filePath || !filePath.trim()) {
  //   throw new Error('Path is not specified.');
  // }

  // if (!callback || typeof callback !== 'function') {
  //   throw new Error('Callback function is not specified.');
  // }

  // filter
  if (options.excludes) {
    for (let i = 0; i < options.excludes.length; i++) {
      if (minimatch(filePath, options.excludes[i], { nocase: true })) {
        return;
      }
    }
  }

  // check the file path status
  fs.stat(filePath, function (err, stats) {
    if (err) {
      throw err;
    }

    if (stats.isDirectory()) {
      fs.readdir(filePath, function (err, files) {
        if (err) {
          throw err;
        }

        files.forEach(function (fileName) {
          walk(path.join(filePath, fileName), options, callback);
        });
      });
    }

    if (stats.isFile()) {
      // filter extname
      if (options.extnames && options.extnames.indexOf(path.extname(filePath)) === -1) {
        return;
      }
      callback(filePath);
    }
  });
}

function transpile(filePath) {
  console.log(`transpiling ${filePath}`);
  const outputFileName = path.join(OUT_DIR, filePath);
  // const serverBuildFileName = path.join('dev_sever_build', filePath.replace('.js', '.mjs'));
  babel.transformFile(filePath, BABEL_OPTIONS, function (err, result) {
    if (err) {
      throw err;
    }
    // result; // => { code, map, ast }
    mkdirp(path.dirname(outputFileName), function (err) {
      if (err) {
        throw err;
      }
      fs.writeFile(outputFileName, result.code, function (err) {
        if (err) {
          throw err;
        }
        console.log(`Finished ${outputFileName}`);
      });
    });

    // mkdirp(path.dirname(serverBuildFileName), function (err) {
    //   if (err) {
    //     throw err;
    //   }
    //   fs.writeFile(serverBuildFileName, result.code, function (err) {
    //     if (err) {
    //       throw err;
    //     }
    //     console.log(`Finished ${serverBuildFileName}`);
    //   });
    // });
  });
}

INCLUDE_FILES.forEach((dir) => {
  walk(dir, { extnames: EXTNAMES, excludes: EXCLUDE_FILES }, transpile);
});

walk('node_modules/', { excludes: ['**/*.js', '**/*.scss'] }, (filePath) => {
  const outputFileName = path.join(OUT_DIR, filePath);
  mkdirp(path.dirname(outputFileName), function (err) {
    if (err) {
      throw err;
    }
    // fs.copyFile(filePath, outputFileName, function (err) {
    //   if (err) {
    //     throw err;
    //   }
    //   console.log(`Copied ${outputFileName}`);
    // });
    fs.createReadStream(filePath).pipe(fs.createWriteStream(outputFileName));
  });
});

preprocess-scss.js

const sass = require('node-sass');

module.exports = function processSass(data, filename) {
  const result = sass.renderSync({
    data: data.replace('${theme}', 'xuse').replace('~', ''),
    file: filename,
    includePaths: ['src', 'node_modules'],
    sourceMap: true,
    sourceComments: true
  }).css;
  return result.toString('utf8');
};