How to use the @jupyterlab/buildutils.Build function in @jupyterlab/buildutils

// Copyright (c) Jupyter Development Team.
// Distributed under the terms of the Modified BSD License.
var data = require('./package.json');
var Build = require('@jupyterlab/buildutils').Build;

var names = Object.keys(data.dependencies).filter(function(name) {
  var packageData = require(name + '/package.json');
  return packageData.jupyterlab !== undefined;
});

var extras = Build.ensureAssets({
  packageNames: names,
  output: './build'
});

module.exports = [
  {
    entry: ['whatwg-fetch', './index.js'],
    output: {
      path: __dirname + '/build',

// Copyright (c) Jupyter Development Team.
// Distributed under the terms of the Modified BSD License.
var data = require('./package.json');
var Build = require('@jupyterlab/buildutils').Build;

var names = Object.keys(data.dependencies).filter(function(name) {
  var packageData = require(name + '/package.json');
  return packageData.jupyterlab !== undefined;
});

var extras = Build.ensureAssets({
  packageNames: names,
  output: './build'
});

module.exports = [
  {
    entry: ['whatwg-fetch', './index.js'],
    output: {
      path: __dirname + '/build',

/*-----------------------------------------------------------------------------
| Copyright (c) Jupyter Development Team.
| Distributed under the terms of the Modified BSD License.
|----------------------------------------------------------------------------*/

var path = require('path');
var fs = require('fs-extra');
var Handlebars = require('handlebars');
var HtmlWebpackPlugin = require('html-webpack-plugin');
var webpack = require('webpack');

var Build = require('@jupyterlab/buildutils').Build;
var package_data = require('./package.json');

// Handle the extensions.
var jlab = package_data.jupyterlab;
var extensions = jlab.extensions;
var mimeExtensions = jlab.mimeExtensions;
Build.ensureAssets({
  packageNames: Object.keys(mimeExtensions).concat(Object.keys(extensions)),
  output: jlab.outputDir
});

fs.ensureDirSync('node_modules/codemirror/mode/prolog');
fs.copySync(path.join(path.resolve(jlab.buildDir),'../../../kernels/yap_kernel/prolog.js'), 'node_modules/codemirror/mode/prolog/prolog.js');
fs.copySync(path.join(path.resolve(jlab.buildDir),'../../../kernels/yap_kernel/meta.js'), 'node_modules/codemirror/mode/meta.js');

// Create the entry point file.

var webpack = require('webpack');
var path = require('path');
var fs = require('fs-extra');
var Handlebars = require('handlebars');
var crypto = require('crypto');
var package_data = require('./package.json');
var Build = require('@jupyterlab/buildutils').Build;

// Ensure a clear build directory.
var buildDir = './build';
if (fs.existsSync(buildDir)) {
  fs.removeSync(buildDir);
}
fs.ensureDirSync(buildDir);

fs.copySync('./package.json', './build/package.json');

// Handle the extensions.
var jlab = package_data.jupyterlab;
var extensions = jlab.extensions;
var mimeExtensions = jlab.mimeExtensions;
Build.ensureAssets({
  packageNames: Object.keys(mimeExtensions).concat(Object.keys(extensions)),

// Copyright (c) Jupyter Development Team.
// Distributed under the terms of the Modified BSD License.
var data = require('./package.json');
var Build = require('@jupyterlab/buildutils').Build;

var names = Object.keys(data.dependencies).filter(function(name) {
  var packageData = require(name + '/package.json');
  return packageData.jupyterlab !== undefined;
});

var extras = Build.ensureAssets({
  packageNames: names,
  output: './build'
});

module.exports = [
  {
    entry: ['whatwg-fetch', './index.js'],
    output: {
      path: __dirname + '/build',

/*-----------------------------------------------------------------------------
| Copyright (c) Jupyter Development Team.
| Distributed under the terms of the Modified BSD License.
|----------------------------------------------------------------------------*/

var path = require('path');
var fs = require('fs-extra');
var Handlebars = require('handlebars');
var HtmlWebpackPlugin = require('html-webpack-plugin');
var webpack = require('webpack');
var DuplicatePackageCheckerPlugin = require('duplicate-package-checker-webpack-plugin');
var Visualizer = require('webpack-visualizer-plugin');

var Build = require('@jupyterlab/buildutils').Build;
var package_data = require('./package.json');

// Handle the extensions.
var jlab = package_data.jupyterlab;
var extensions = jlab.extensions;
var mimeExtensions = jlab.mimeExtensions;

var extraConfig = Build.ensureAssets({
  packageNames: Object.keys(mimeExtensions).concat(Object.keys(extensions)),
  output: jlab.outputDir
});

// Create the entry point file.
var source = fs.readFileSync('index.js').toString();
var template = Handlebars.compile(source);
var data = {

/*-----------------------------------------------------------------------------
| Copyright (c) Jupyter Development Team.
| Distributed under the terms of the Modified BSD License.
|----------------------------------------------------------------------------*/

var plib = require('path');
var fs = require('fs-extra');
var Handlebars = require('handlebars');
var HtmlWebpackPlugin = require('html-webpack-plugin');
var webpack = require('webpack');
var DuplicatePackageCheckerPlugin = require('duplicate-package-checker-webpack-plugin');
var BundleAnalyzerPlugin = require('webpack-bundle-analyzer')
  .BundleAnalyzerPlugin;

var Build = require('@jupyterlab/buildutils').Build;
var WPPlugin = require('@jupyterlab/buildutils').WPPlugin;
var package_data = require('./package.json');

// Handle the extensions.
var jlab = package_data.jupyterlab;
var extensions = jlab.extensions;
var mimeExtensions = jlab.mimeExtensions;
var packageNames = Object.keys(mimeExtensions).concat(Object.keys(extensions));

// Ensure a clear build directory.
var buildDir = plib.resolve(jlab.buildDir);
if (fs.existsSync(buildDir)) {
  fs.removeSync(buildDir);
}
fs.ensureDirSync(buildDir);

// Copyright (c) Jupyter Development Team.
// Distributed under the terms of the Modified BSD License.

var data = require('./package.json');
var Build = require('@jupyterlab/buildutils').Build;

var names = Object.keys(data.dependencies).filter(function (name) {
  var packageData = require(name + '/package.json');
  return packageData.jupyterlab !== undefined;
});

var extras = Build.ensureAssets({
  packageNames: names,
  output: './build'
});

module.exports = [
  {
    entry: ['whatwg-fetch', './index.js'],
    output: {
      path: __dirname + '/build',

var data = require('./package.json');
var Build = require('@jupyterlab/buildutils').Build;

var names = Object.keys(data.dependencies).filter(function(name) {
  var packageData = require(name + '/package.json');
  return packageData.jupyterlab !== undefined;
});

Build.ensureAssets({
  packageNames: names,
  output: './build'
});

var childProcess = require('child_process');
var fs = require('fs-extra');
var glob = require('glob');
var path = require('path');
var sortPackageJson = require('sort-package-json');
var Build = require('@jupyterlab/buildutils').Build;

var corePackage = require('./package.json');
corePackage.jupyterlab.extensions = {};
corePackage.jupyterlab.mimeExtensions = {};
corePackage.dependencies = {};

var basePath = path.resolve('..');
var packages = glob.sync(path.join(basePath, 'packages/*'));
packages.forEach(function(packagePath) {

   var dataPath = path.join(packagePath, 'package.json');
   try {
    var data = require(dataPath);
  } catch (e) {
    return;
  }