old_contents: const path = require('path');
  const fse = require('fs-extra');
  const glob = require('glob');
  
  function copyTypings(from, to) {
    const files = glob.sync('**/*.d.ts', { cwd: from });
    const cmds = files.map(file => fse.copy(path.resolve(from, file), path.resolve(to, file)));
    return Promise.all(cmds);
  }
  
  function copyReadme() {
    return fse.copyFile(path.resolve(__dirname, '..', 'README.md'), path.resolve(__dirname, 'build', 'README.md'));
  }
  
  function createPackageFile() {
    return new Promise((resolve) => {
      fse.readFile(path.resolve(__dirname, 'package.json'), 'utf8', (err, data) => {
        if (err) {
          throw err;
        }
  
        resolve(data);
      });
    })
      .then(data => JSON.parse(data))
      .then((packageData) => {
        const newPackage = {
          ...packageData,
          main: './dist/material-ui-pickers.cjs.js',
          module: './src/index.js',
          types: './src/index.d.ts',
          private: false,
        };
  
        return new Promise((resolve) => {
          const buildPath = path.resolve(__dirname, 'build', 'package.json');
          const data = JSON.stringify(newPackage, null, 2);
          fse.writeFile(buildPath, data, (err) => {
            if (err) throw err;
            console.log(`Created package.json in ${buildPath}`);
            resolve();
          });
        });
      });
  }
  
  createPackageFile()
    .then(() => copyTypings(path.resolve(__dirname, 'src'), path.resolve(__dirname, 'build/src')))
    .then(() => copyReadme());
  
new_contents: const path = require('path');
  const fse = require('fs-extra');
  const glob = require('glob');
  
  function copyTypings(from, to) {
    const files = glob.sync('**/*.d.ts', { cwd: from });
    const cmds = files.map(file => fse.copy(path.resolve(from, file), path.resolve(to, file)));
    return Promise.all(cmds);
  }
  
  function copyReadme() {
    return fse.copyFile(path.resolve(__dirname, '..', 'README.md'), path.resolve(__dirname, 'build', 'README.md'));
  }
  
  function createPackageFile() {
    return new Promise((resolve) => {
      fse.readFile(path.resolve(__dirname, 'package.json'), 'utf8', (err, data) => {
        if (err) {
          throw err;
        }
  
        resolve(data);
      });
    })
      .then(data => JSON.parse(data))
      .then((packageData) => {
        const newPackage = {
          ...packageData,
          main: './dist/material-ui-pickers.cjs.js',
          module: './src/index.js',
          private: false,
        };
  
        return new Promise((resolve) => {
          const buildPath = path.resolve(__dirname, 'build', 'package.json');
          const data = JSON.stringify(newPackage, null, 2);
          fse.writeFile(buildPath, data, (err) => {
            if (err) throw err;
            console.log(`Created package.json in ${buildPath}`);
            resolve();
          });
        });
      });
  }
  
  createPackageFile()
    .then(() => copyTypings(path.resolve(__dirname, 'src'), path.resolve(__dirname, 'build/src')))
    .then(() => copyReadme());
  
subject: Remove redundant types declaration