Unifying Rollup options

Rollup 0.48 introduces a few changes to the options object, because the current options are confusingly different between the CLI and the options exported by your config file.

Changes to the config file

• entry is now input
• sourceMap and sourceMapFile are now sourcemap and sourcemapFile (note casing)
• moduleName is now name
• useStrict is now strict

The dest and format options are now grouped together as a single output: { file, format, ... } object. output can also be an array of { file, format, ... } objects, in which case it behaves similarly to the current targets. Other output options — exports, paths and so on — can be added to the output object (though they will fall back to their top-level namesakes, if unspecified).

So this…

// old rollup.config.js
export default {
  entry: 'src/main.js',
  dest: 'public/bundle.js',
  format: 'iife',
  moduleName: 'App',
  sourceMap: true
};

…would become this:

// new rollup.config.js
export default {
  input: 'src/main.js',
  output: {
    file: 'public/bundle.js',
    format: 'iife',
    name: 'App',
    sourcemap: true
  }
};

A config with multiple outputs (say, a CommonJS main and a ESM module output) might look like this:

import pkg from './package.json';

export default {
  input: 'src/index.js',
  output: [
    { file: pkg.main, format: 'umd', name: 'MyLibrary' },
    { file: pkg.module, format: 'es' }
  ],

  // other output options specified here will be shared by
  // all outputs, unless overridden
  sourcemap: true
};

Changes to the API

The same changes apply if you’re using the API directly:

rollup.rollup({
  input: 'src/main.js'
}).then(bundle => {
  return bundle.write({
    file: 'public/bundle.js',
    format: 'iife',
    name: 'App',
    sourcemap: true
  });
});

Changes to the CLI

The --output and --format can now also be specified as --output.file and --output.format respectively. The shorthand -o and -f options are unchanged.