Can I have multiple entry points using Rollup with Gulp? - gulp

Question

I have a gulpfile.js that uses Rollup to build two distinct JS files (front-end and admin). The rollup.config.js method allows multiple entry points and bundles to be specified, but to achieve this with Gulp I've had to do a bit of a nasty workaround.
const javascripts = [
{
src: './app/assets/javascripts/main.js',
dest: './public/javascripts/main.js',
moduleName: 'main'
},
{
src: './admin/assets/javascripts/admin.js',
dest: './public/admin/javascripts/admin.js',
moduleName: 'admin'
}
]
gulp.task('js:compile', ()=> {
javascripts.forEach((item)=> {
return rollup({
input: item.src,
plugins: [
builtins(),
nodeResolve({ jsnext: true, browser: true }),
commonjs({
include: 'node_modules/**',
exclude: 'node_modules/rollup-plugin-node-globals/**',
ignoreGlobal: false,
sourceMap: true,
main: true,
browser: true
}),
json(),
buble()
]
}).then(function (bundle) {
return bundle.write({
format: 'iife',
name: item.moduleName,
file: item.dest
})
})
})
})
Is there a better way of achieving this? I'm not averse to reorganising my files to use globbing or something similar.
EDIT: I've updated it to use Node's fs rather than having to specify each script but this still feels a bit clunky to me.
gulp.task('js:compile', () => {
fs.readdir('./app/assets/javascripts', (err, files) => {
if(err) throw err
files.forEach((file) => {
if(!file.match('.js')) return false
return rollup({
input: `./app/assets/javascripts/${file}`,
plugins: [
builtins(),
nodeResolve({ jsnext: true, browser: true }),
commonjs({
include: 'node_modules/**',
exclude: 'node_modules/rollup-plugin-node-globals/**',
ignoreGlobal: false,
sourceMap: true,
main: true,
browser: true
}),
json(),
buble()
]
}).then((bundle) => {
return bundle.write({
format: 'iife',
name: file.split('.')[-2],
file: `./public/javascripts/${file}`
})
}).catch( (e) => console.log(e) )
})
})
})

Answer 1

Now, you can just return an array of objects from rollup.config.js.
So if you
need to compile a single file, return the object export default {...}
need to compile multiple files, return list of objects export default [{...},{...},{...}, ...]
Look here for inspiration
cheatsheet

Answer 2

You can now use https://github.com/alfredosalzillo/rollup-plugin-multi-input, it also preserve directory tree in output dir.
import multiInput from 'rollup-plugin-multi-input';
export default {
input: ['src/**/*.js'],
experimentalCodeSplitting: true,
output: {
format: 'esm',
dir: 'dist'
},
plugins: [ multiInput() ],
};