Spike: Webpack 2 tree shaking

[coopy]

I'd like to support the current use of selective imports with descructuring import { foo } from 'lib' without taking a bundle weight hit. Let's see how much work it'd be to upgrade to webpack 2 and enable tree shaking (and how much size savings this would give us).

[okonet]

Is it implemented or won't be?

[ryan-roemer]

@boygirl and @coopy know more about this than I do, but we have audited and will continue to audit our bundles to make sure we have either (1) a plugin that tree shakes (like lodash) or (2) manually ensure that we do one-off imports and never have an import with unused exports. We check things with tools like https://github.com/FormidableLabs/inspectpack#parse which can detect multiple es5 / cjs and es-next-style multiple re-exports (the anti-pattern tree-shaking addresses).

My hunch is we'll wait on issues like:

• tree-shaking with lodash-es webpack/webpack#1750
• Mention "bad practise" approach lodash/babel-plugin-lodash#75
• Bundling pre-ES6 modules rollup/rollup#45

before looking to convert our one-off imports to first class imports that would even implicate tree shaking...