Consider bundling Snowpack #1950

Rich-Harris · 2020-12-12T18:27:03Z

Rich-Harris
Dec 12, 2020

Snowpack has a very large number of dependencies — significantly larger than, say, webpack, which is often used as an example of a package with an unwieldy dependency graph:

This is reflected in the time it takes to npm install snowpack or for Snowpack to start up. Installing Snowpack into a fresh project results in 44MB of node_modules.

$ time npm install snowpack
npm WARN deprecated rollup-plugin-inject@3.0.2: This package has been deprecated and is no longer maintained. Please use @rollup/plugin-inject.

> esbuild@0.8.22 postinstall /private/var/folders/lh/_jn0hqjs4dg2rvk3kmjvmvhc0000gp/T/tmp.yH3QR9Kj/unbundled/node_modules/esbuild
> node install.js

npm notice created a lockfile as package-lock.json. You should commit this file.
npm WARN unbundled No description
npm WARN unbundled No repository field.
npm WARN unbundled No license field.

+ snowpack@2.18.3
added 267 packages from 213 contributors and audited 267 packages in 7.861s

31 packages are looking for funding
  run `npm fund` for details

found 0 vulnerabilities

npm install snowpack  6.34s user 2.25s system 103% cpu 8.334 total

A useful point of comparison is wmr, which is roughly similarly scoped but yields 2.8MB of node_modules:

time npm install wmr
npm notice created a lockfile as package-lock.json. You should commit this file.
npm WARN wmr-test No description
npm WARN wmr-test No repository field.
npm WARN wmr-test No license field.

+ wmr@1.0.0
added 2 packages from 6 contributors and audited 2 packages in 0.796s
found 0 vulnerabilities

npm install wmr  0.58s user 0.13s system 58% cpu 1.212 total

wmr doesn't achieve this outcome by not having dependencies, it achieves it by bundling them. Snowpack could do the same. I rustled up a proof of concept here, and the results speak for themselves:

	npm install time	startup time	node_modules size
unbundled (current)	~8s	~0.38s	44MB
bundled	~1s	~0.25s	5.9MB

Installation/startup times are obviously approximate as there's some variance, but the bundled version is reliably significantly faster.

This proof of concept uses esbuild with only very minor changes to the source code. For even better startup time results, it would make sense to use code-splitting and dynamically import modules (for example only loading the build command if the user ran snowpack build) — this isn't currently possible with esbuild (which can only do code-splitting for ESM builds) but would be trivial with Rollup.