copy.config.js

const orgCopyConfig = require('@ionic/app-scripts/config/copy.config');


orgCopyConfig.include.push({
    src: 'node_modules/angularfire2/node_modules/firebase/firebase.js',
    dest: 'www/assets/firebase.js'
});

module.exports = orgCopyConfig;

rollup.config.js

var nodeResolve = require('rollup-plugin-node-resolve');
var commonjs = require('rollup-plugin-commonjs');
var globals = require('rollup-plugin-node-globals');
var builtins = require('rollup-plugin-node-builtins');
var json = require('rollup-plugin-json');

// https://github.com/rollup/rollup/wiki/JavaScript-API

var rollupConfig = {
    /**
     * entry: The bundle's starting point. This file will
     * be included, along with the minimum necessary code
     * from its dependencies
     */
    entry: 'src/app/main.dev.ts',

    /**
     * sourceMap: If true, a separate sourcemap file will
     * be created.
     */
    sourceMap: true,

    /**
     * format: The format of the generated bundle
     */
    format: 'iife',

    /**
     * dest: the output filename for the bundle in the buildDir
     */
    dest: 'main.js',


    // Add this to avoid Eval errors
    useStrict: false,

    /**
     * plugins: Array of plugin objects, or a single plugin object.
     * See https://github.com/rollup/rollup/wiki/Plugins for more info.
     */
    plugins: [
        builtins(),
        commonjs({
            include: [
                'node_modules/rxjs/**',
                'node_modules/firebase/**',
                'node_modules/angularfire2/**',
                'node_modules/@ionic/storage/**',
                'node_modules/localforage/**'
            ],
            namedExports: {
                'node_modules/firebase/firebase.js': ['initializeApp', 'auth', 'database'],
                'node_modules/angularfire2/node_modules/firebase/firebase-browser.js': ['initializeApp', 'auth', 'database'],
            }
        }),
        nodeResolve({
            module: true,
            jsnext: true,
            main: true,
            browser: true,
            extensions: ['.js']
        }),
        globals(),
        json()
    ]

};

if (process.env.IONIC_ENV == 'prod') {
    // production mode
    rollupConfig.entry = '{{TMP}}/app/main.prod.ts';
    rollupConfig.sourceMap = false;
}

module.exports = rollupConfig;