rollup.config.js

// rollup.config.js
import resolve from 'rollup-plugin-node-resolve';
import replace from 'rollup-plugin-replace';
import commonjs from 'rollup-plugin-commonjs';
import hash from 'rollup-plugin-hash';
import builtins from 'rollup-plugin-node-builtins';
import { terser } from 'rollup-plugin-terser';

const INPUT_FILE = 'src/js/index.js';
const OUTPUT_FILE = '_site/js/index.js';

export default {
  input: INPUT_FILE,
  output: {
    file: OUTPUT_FILE,
    format: 'iife',
    name: 'TechWeeklies',
  },
  plugins: [
    // Replace calls to process.env with build-time variables
    replace({
      'process.env.NODE_ENV': JSON.stringify(
        process.env.NODE_ENV || 'production'
      ),
      'process.env.GA_TRACKING_ID': JSON.stringify(
        process.env.GA_TRACKING_ID || ''
      ),
    }),
    // Resolve modules for bundling using node's search algorithtm
    resolve(),
    // Allow resolving CommonJS modules
    commonjs(),
    builtins(),
    ifProduction(terser),
    ifProduction(() =>
      hash({
        dest: '_site/js/index.[hash:10].js',
        replace: true,
        manifest: '_intermediate/rollup-manifest.json',
      })
    ),
  ],
};

function ifProduction(plugin) {
  return process.env.NODE_ENV === 'production' ? plugin() : null;
}