compares the popular module bundlers of today (October 2016)
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JavaScript Module Bundling Comparison


  • compares the popular module bundlers of today (October 2016) using the latest versions (includes betas)
  • see the underlying structural differences and similarities between each bundler
  • import { get } from 'lodash' imports every lodash function along with it, while import get from 'lodash/get' imports just the one function. This is the reason why both default and direct importing are tested.

The program

  1. src/index.js imports fn1()...8() using ES6 modules
  2. executes fn1()...8()
  3. all functions call lodash.get()
  4. fn9() is imported and called from fn8()
  5. fn10() is imported but not called from fn8() (tree-shakeable)
  6. console.logs fn1()...9()

Stats (ordered by size desc)

Default import

bundle-jspm.js 554K
bundle-browserify.js 525K
bundle-browserify-rollup.js 523K
bundle-webpack.js 473K
bundle-rollup.js NONE (cannot import lodash directly)

Default import + UglifyJS

bundle-webpack.min.js 145K
bundle-browserify.min.js 141K
bundle-jspm.min.js 141K
bundle-browserify-rollup.min.js 139K
bundle-rollup.js NONE (cannot import lodash directly)

Direct import

bundle-jspm.js 45K
bundle-webpack.js 43K
bundle-browserify.js 37K
bundle-browserify-rollup.js 30K
bundle-rollup.js 29K

Direct import + UglifyJS

bundle-jspm.min.js 24K
bundle-webpack.min.js 22K
bundle-browserify.min.js 19K
bundle-browserify-rollup.min.js 13K
bundle-rollup.min.js 12K


  • Rollup struggles with non-ES6 modules; import { get } from 'lodash' does not load get into the bundle, but import { get } from 'lodash-es' does.
  • As the tests show, tree-shaking does not work on unused methods from objects that are used. This is why when lodash is imported by default, Rollup cannot remove all of the unused methods.

To run

  • npm run all to concurrently create bundles and then concurrently create minified bundles
  • npm run all:min
  • ls -lah -S -R dist/* | awk '{print $9, $5}' to read the bundle filesizes, ordered by size desc
Basically Nolan Lawson's Rollup Comparison, but with a lodash dependency and an unused export.