gulpfile.js

/**
 * Build scripts
 *
 * Copyright (c) 2017-2025 Alex Grant (@localnerve), LocalNerve LLC
 * Copyrights licensed under the BSD License. See the accompanying LICENSE file for terms.
 */

const fs = require('fs');
const path = require('path');
const util = require('util');
const { spawn } = require('child_process');
const gulp = require('gulp');
const webpack = require('webpack');
const TerserPlugin = require('terser-webpack-plugin');
const { getSourceDirs, srcRoot } = require('./src/utils/dirs');

const jsBundle = 'bundle.js';

/**
 * Returns an array of webpack config objects that assume these constraints:
 * 1. Produces one .js only bundle named `jsBundle`.
 * 2. Entry point is index.js
 *
 * @param {String} env - The target env, 'production' for production.
 * @param {Array} dirs - toplevel directories under srcRoot.
 * @returns {Array} Webpack config objects.
 */
async function getWebpackConfig (env, dirs) {
  const prod = env === 'production';
  const definitions = {
    DEBUG: !prod,
    'process.env': {
      NODE_ENV: JSON.stringify(env)
    }
  };
  const plugins = [
    new webpack.DefinePlugin(definitions)
  ];
  const optimization = {};

  if (prod) {
    optimization.minimizer = [
      new TerserPlugin({
        terserOptions: {
          compress: {
            warnings: false
          },
          output: {
            comments: false
          }
        }
      })
    ];
  }

  // special case for jump-scroll, revisit...
  const dir = dirs.find(dir => dir.includes('jump-scroll'));
  if (dir) {
    const { spawn } = require('child_process');
    const cp = spawn('npm', ['run', 'build'], {
      stdio: 'inherit',
      cwd: dir
    });
    const result = new Promise((resolve, reject) => {
      cp.on('close', code => {
        if (code === 0) {
          resolve();
        } else {
          reject();
        }
      });
    });
    await result;
    fs.copyFileSync(
      path.join(path.resolve(dir), 'dist/jump-scroll.js'),
      path.join(path.resolve(dir), `${jsBundle}`)
    );
  }

  const webpackDirs = dirs.filter(dir => !dir.includes('jump-scroll'));
  return webpackDirs.map(dir => ({
    mode: prod ? 'production' : 'development',
    entry: `${path.join(dir, 'index.js')}`,
    output: {
      path: path.resolve(dir),
      filename: `${jsBundle}`
    },
    module: {
      rules: [{
        test: /\.js$/,
        exclude: /^\/node_modules/,
        loader: 'babel-loader'
      }]
    },
    plugins,
    optimization
  }));
}

/**
 * Creates js bundles for all top level directories under `srcRoot`.
 *
 * @param {String} env - "production" for production.
 * @returns {Promise} Resolves to undefined on completion.
 */
function createBundle (env) {
  return getSourceDirs()
    .then(getWebpackConfig.bind(null, env))
    .then(webpackConfigs => util.promisify(webpack)(webpackConfigs))
    .then(stats => {
      if (stats.hasErrors()) {
        throw stats.toJson().errors;
      }
    });
}

/**
 * Run `npm install` for any src directory that needs it.
 *
 * @returns {Promise} That resolves if all npm installs succeed, rejects otherwise.
 */
function runPackageInstalls () {
  return getSourceDirs()
    .then(dirs => {
      const pkgDirs = dirs.filter(dir => {
        let exists = false;
        try {
          fs.accessSync(path.join(dir, 'package.json'));
          exists = true;
        } catch (e) {
          exists = false;
        }
        return exists;
      });

      return Promise.all(pkgDirs.map(pkgDir => {
        const cp = spawn('npm', ['install'], {
          cwd: pkgDir
        });
        return new Promise((resolve, reject) => {
          cp.on('close', code => {
            if (code !== 0) {
              return reject();
            }
            return resolve();
          });
          cp.on('error', reject);
        });
      }));
    });
}

// Define the build tasks:

gulp.task(
  'copy', () => gulp.src([
    `${srcRoot}/**/*.html`,
    `${srcRoot}/**/*.css`,
    `${srcRoot}/**/*.jpg`,
    `${srcRoot}/**/${jsBundle}`,
    `${srcRoot}/**/*worker.js`,
    `${srcRoot}/**/node_modules/**`,
    `!${srcRoot}/horizontal-pager/node_modules`,
    `!${srcRoot}/horizontal-pager/node_modules/**`,
    `!${srcRoot}/jump-scroll/node_modules`,
    `!${srcRoot}/jump-scroll/node_modules/**`,
    `!${srcRoot}/**/test`,
    `!${srcRoot}/**/test/**`,
  ], {
    encoding: false
  }).pipe(gulp.dest('dist'))
);

gulp.task('webpack', () => createBundle('production'));
gulp.task('webpack-dev', () => createBundle('development'));
gulp.task('installs', runPackageInstalls);