fancy-rollup

Multi-process Rollup wrapper.

Purpose

Rollup has the ability to create multiple bundles from a single invocation of the rollup command. All you need to do is export an array of build configurations from your configuration file. Great, right?

Well, using this method, a single Rollup process will simply create all the configured bundles in sequence. Unfortunately, that can get pretty slow. Computers are great at parallelization, so what you probably want to do instead is run your builds concurrently.

To accomplish that, you could create a configuration file per build and invoke rollup once for each of those files. Once you've figured out how to coordinate all that, you'd probably turn your attention to reporting progress from each of the builds in a comprehensive way.

What fancy-rollup does is handle all this for you. Firstly, it will start multiple Node processes that each run Rollup, using all of your machine's available processing power and dramatically speeding up builds. Secondly, it comes with multiple reporters that provide a nice overview of build progress.

Installation

For convenience, you can install fancy-rollup globally:

yarn global add fancy-rollup

However, you probably want to make it a devDependency of your package instead:

yarn add fancy-rollup --dev

Configuration

Like Rollup itself, fancy-rollup will read rollup.config.js in the current working directory. Just export an array of build configurations and you're good to go.

Usage

Simply invoke fancy-rollup from the command line:

fancy-rollup

An API for invoking fancy-rollup from your JavaScript code is in the works.

Options

Option	Description
-c <filename> --config	Specify config file name. Identical to Rollup's option.
-t <id> --target	Select targets to build. May be specified multiple times. Default is all.
-r <name> --reporter	Select style for reporting progress. See below.
-p <number> --concurrency	Limit number of concurrent builds. Default is one per CPU core.
-v --version	Show version number.
-h --help	Show help.

Reporters

Reporter	Description
interactive	Tailing logger with progress bar and timer. Default.
dumb	Tailing logger only. Default for non-TTY environments.
simple	Live-updating one-line status.
list	Live-updating checklist using Listr.
essential	Rollup output only.
silent	No output.

Rollup Versioning

It's generally a good idea to lock down the version of Rollup that you want to use for bundling. Specifying an exact version lets you avoid API inconsistencies and other unexpected behavior.

This is accomplished by simply installing the correct rollup package alongside fancy-rollup. In other words, put both of them in the same package.json file so that yarn (or npm install) puts them under the same node_modules directory.

If fancy-rollup cannot find rollup under the package directory's node_modules, it will check the parent directory's, then that one's parent directory's, etc. This is Node's standard module resolution in action.

If none of the parent directories contain a rollup installation either, fancy-rollup will fall back to using its own version. You can check which one that is by consulting package.json.

Author

Tim De Pauw

License

MIT