bclinkinbeard / tree-shaking-comparison

Compare tree shaking of Rollup and Webpack 2 (beta)

Compare tree shaking of Rollup and Webpack 2 (beta)

Before you begin, npm install to install all dependencies

Then npm run rollup / npm run webpack to bundle using one or the other, or npm run bundle to bundle using both projects.

The entry file consists of just this code:

import { permute } from 'd3-array';

permute();

The permute export from d3-array is a single function with no dependencies, weighing in at 161 bytes. Its full contents are as follows:

export default function(array, indexes) {
  var i = indexes.length, permutes = new Array(i);
  while (i--) permutes[i] = array[indexes[i]];
  return permutes;
}

The resulting bundles, therefore, should have a similar file size if not smaller once minification is applied. Instead, as of this writing, Rollup 0.36.3 produces a 3KB minified bundle and Webpack 2.1.0-beta.25 produces a 4KB minified bundle.

In both cases, code is included in the bundle that was not referenced from the entry file or from the permute module in d3-array.

All bundles have been included in the repo for the sake of convenience.