Maintenance: Enable syntax minification for dead code elimination #33001

mrginglymus · 2025-11-11T08:10:45Z

What I did

SB 10 does not minify code. Whilst this makes debugging considerably easier, it also means that dead code elimination is not applied (e.g. conditional blocks protected by compile-time constants like process.env.NODE_ENV).

Thankfully, esbuild provides three separate options for minification. Enabling minifySyntax will apply dead code elimination, as well as a couple of other relatively harmless optimisations. A brief scan suggests these include things like:

moving var declarations to a single statement
compressing return statements
replacing true with !0
removing unecessary {} around single-line blocks

However, critically, it preserves whitespace and identifiers.

This also appears to give you a small (~10%) saving in runtime code, though much of this may get eaten by gzip

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

stories
unit tests
integration tests
end-to-end tests

Manual testing

Please ensure, the output dist of the storybook packages (just pick a few) (and a few entry-points of core) contain human readable code.

Documentation

Add or update documentation reflecting your changes
If you are deprecating/removing a feature, make sure to update
MIGRATION.MD

Checklist for Maintainers

When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli-storybook/src/sandbox-templates.ts
Make sure this PR contains one of the labels below:
Available labels
- bug: Internal changes that fixes incorrect behavior.
- maintenance: User-facing maintenance tasks.
- dependencies: Upgrading (sometimes downgrading) dependencies.
- build: Internal-facing build tooling & test updates. Will not show up in release changelog.
- cleanup: Minor cleanup style change. Will not show up in release changelog.
- documentation: Documentation only changes. Will not show up in release changelog.
- feature request: Introducing a new feature.
- BREAKING CHANGE: Changes that break compatibility in some way with current major version.
- other: Changes that don't fit in the above categories.

🦋 Canary release

This PR does not have a canary release associated. You can request a canary release of this pull request by mentioning the @storybookjs/core team here.

core team members can create a canary release here or locally with gh workflow run --repo storybookjs/storybook publish.yml --field pr=<PR_NUMBER>

Summary by CodeRabbit

Chores
- Build output now produces more compact/minified syntax for smaller bundles and faster load times.
- Tooling dependencies updated to permit newer bundler versions and refreshed icon package versions.
Bug Fixes
- Error reporting now includes explicit, consistent error names so messages and diagnostics show clearer named error identities.

nx-cloud · 2025-11-11T08:13:10Z

View your CI Pipeline Execution ↗ for commit 0d98abb

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☁️ Nx Cloud last updated this comment at 2025-11-13 10:25:46 UTC

ndelangen · 2025-11-12T10:58:33Z

@mrginglymus It does not look like the are actually any size-changes detected?

mrginglymus · 2025-11-12T12:19:37Z

This branch might just be out of date, but next is showing 3.4mb for globals-runtime.js, and this branch showing 2.8mb.

Even allowing for a different set of features, react-dom is down from 235.6kb to 232.9kb,

not sure where the bulk of that is coming from then...

oh - next has @react-aria in it, which this branch doesn't

JReinhold · 2025-11-12T12:37:27Z

I'm okay with this change

storybook-app-bot · 2025-11-12T12:46:47Z

Package Benchmarks

^{Commit: 0d98abb, ran on 21 November 2025 at 11:14:56 UTC}

The following packages have significant changes to their size or dependencies:

`@storybook/addon-a11y`

	Before	After	Difference
Dependency count	2	2	0
Self size	181 KB	414 KB	🚨 +232 KB 🚨
Dependency size	2.97 MB	2.97 MB	0 B
Bundle Size Analyzer	Link	Link

`@storybook/addon-vitest`

	Before	After	Difference
Dependency count	2	6	🚨 +4 🚨
Self size	376 KB	441 KB	🚨 +66 KB 🚨
Dependency size	338 KB	570 KB	🚨 +232 KB 🚨
Bundle Size Analyzer	Link	Link

`@storybook/builder-vite`

	Before	After	Difference
Dependency count	17	11	🎉 -6 🎉
Self size	304 KB	291 KB	🎉 -13 KB 🎉
Dependency size	2.00 MB	1.30 MB	🎉 -701 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/builder-webpack5`

	Before	After	Difference
Dependency count	191	187	🎉 -4 🎉
Self size	75 KB	66 KB	🎉 -9 KB 🎉
Dependency size	32.19 MB	31.98 MB	🎉 -215 KB 🎉
Bundle Size Analyzer	Link	Link

`storybook`

	Before	After	Difference
Dependency count	39	44	🚨 +5 🚨
Self size	19.65 MB	21.70 MB	🚨 +2.05 MB 🚨
Dependency size	16.40 MB	17.16 MB	🚨 +755 KB 🚨
Bundle Size Analyzer	Link	Link

`@storybook/angular`

	Before	After	Difference
Dependency count	191	187	🎉 -4 🎉
Self size	118 KB	114 KB	🎉 -3 KB 🎉
Dependency size	30.31 MB	30.00 MB	🎉 -317 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/ember`

	Before	After	Difference
Dependency count	195	191	🎉 -4 🎉
Self size	15 KB	15 KB	0 B
Dependency size	28.91 MB	28.69 MB	🎉 -224 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/html-vite`

	Before	After	Difference
Dependency count	20	14	🎉 -6 🎉
Self size	22 KB	22 KB	0 B
Dependency size	2.34 MB	1.63 MB	🎉 -715 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/nextjs`

	Before	After	Difference
Dependency count	537	533	🎉 -4 🎉
Self size	645 KB	645 KB	🚨 +230 B 🚨
Dependency size	59.13 MB	58.91 MB	🎉 -225 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/nextjs-vite`

	Before	After	Difference
Dependency count	128	124	🎉 -4 🎉
Self size	1.12 MB	1.12 MB	🚨 +224 B 🚨
Dependency size	21.95 MB	21.72 MB	🎉 -229 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/preact-vite`

	Before	After	Difference
Dependency count	20	14	🎉 -6 🎉
Self size	13 KB	13 KB	0 B
Dependency size	2.33 MB	1.61 MB	🎉 -715 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/react-native-web-vite`

	Before	After	Difference
Dependency count	160	156	🎉 -4 🎉
Self size	30 KB	30 KB	🎉 -1 B 🎉
Dependency size	23.13 MB	22.90 MB	🎉 -231 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/react-vite`

	Before	After	Difference
Dependency count	118	114	🎉 -4 🎉
Self size	35 KB	35 KB	🎉 -130 B 🎉
Dependency size	19.75 MB	19.52 MB	🎉 -229 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/react-webpack5`

	Before	After	Difference
Dependency count	277	273	🎉 -4 🎉
Self size	24 KB	24 KB	🚨 +12 B 🚨
Dependency size	44.08 MB	43.85 MB	🎉 -225 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/server-webpack5`

	Before	After	Difference
Dependency count	203	199	🎉 -4 🎉
Self size	16 KB	16 KB	0 B
Dependency size	33.45 MB	33.23 MB	🎉 -224 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/svelte-vite`

	Before	After	Difference
Dependency count	24	19	🎉 -5 🎉
Self size	56 KB	56 KB	🚨 +12 B 🚨
Dependency size	27.00 MB	26.75 MB	🎉 -255 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/sveltekit`

	Before	After	Difference
Dependency count	25	20	🎉 -5 🎉
Self size	56 KB	56 KB	🎉 -24 B 🎉
Dependency size	27.06 MB	26.80 MB	🎉 -255 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/vue3-vite`

	Before	After	Difference
Dependency count	114	109	🎉 -5 🎉
Self size	35 KB	36 KB	🚨 +224 B 🚨
Dependency size	44.15 MB	43.90 MB	🎉 -254 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/web-components-vite`

	Before	After	Difference
Dependency count	21	15	🎉 -6 🎉
Self size	19 KB	19 KB	0 B
Dependency size	2.37 MB	1.65 MB	🎉 -715 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/cli`

	Before	After	Difference
Dependency count	173	188	🚨 +15 🚨
Self size	773 KB	838 KB	🚨 +64 KB 🚨
Dependency size	66.62 MB	71.38 MB	🚨 +4.76 MB 🚨
Bundle Size Analyzer	Link	Link

`@storybook/codemod`

	Before	After	Difference
Dependency count	166	170	🚨 +4 🚨
Self size	30 KB	30 KB	🎉 -11 B 🎉
Dependency size	65.19 MB	67.91 MB	🚨 +2.72 MB 🚨
Bundle Size Analyzer	Link	Link

`create-storybook`

	Before	After	Difference
Dependency count	40	45	🚨 +5 🚨
Self size	999 KB	1.45 MB	🚨 +453 KB 🚨
Dependency size	36.05 MB	38.86 MB	🚨 +2.81 MB 🚨
Bundle Size Analyzer	node	node

ndelangen · 2025-11-12T13:19:14Z

@mrginglymus I tried to add another thing to this PR, but git told me I'm not authorized for some reason?

https://github.com/storybookjs/storybook/pull/33028/files

mrginglymus · 2025-11-12T14:10:08Z

@mrginglymus I tried to add another thing to this PR, but git told me I'm not authorized for some reason?

https://github.com/storybookjs/storybook/pull/33028/files

@ndelangen whoops! sorry, I must have unchecked the allow edits by maintainers...

ndelangen · 2025-11-12T14:26:59Z

I added a few more things to this PR:

regen lockfile
remove the keepnames option, reducing size further

I had to add a name property to the StorybookError class for that.

ndelangen · 2025-11-12T14:37:38Z

It's odd how the size reporting is completely different from when I had the fork PR open 😕

ndelangen · 2025-11-12T16:38:55Z

@mrginglymus I'm looking at the dist, and there are plenty of unused variables:

mrginglymus · 2025-11-12T21:03:12Z

Those ones from polished are to be expected; the calls to curry aren't marked as /* @__PURE__ */ so esbuild won't remove them. What's odd is that adding that annotation also doesn't appear to fix it...

mrginglymus · 2025-11-12T21:18:47Z

You can work around this with deep imports (import darken from 'polished/lib/color/darken') but it won't make a huge difference.

…ackages

Enable syntax minification for dead code elimination

1517a97

yannbf added maintenance User-facing maintenance tasks performance issue ci:normal labels Nov 11, 2025

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yannbf changed the title ~~Enable syntax minification for dead code elimination~~ Maintenance: Enable syntax minification for dead code elimination Nov 11, 2025

yannbf requested a review from JReinhold November 11, 2025 15:17

yannbf assigned JReinhold Nov 11, 2025

ndelangen added ci:merged Run the CI jobs that normally run when merged. and removed ci:normal labels Nov 12, 2025

ndelangen assigned ndelangen and unassigned JReinhold Nov 12, 2025

Merge branch 'next' into pr/mrginglymus/33001

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ndelangen approved these changes Nov 12, 2025

View reviewed changes

ndelangen added 2 commits November 12, 2025 14:15

we do not need this anymore, now that we're no longer minify

1d9109d

remove comment

b477d5e

ndelangen added 4 commits November 12, 2025 14:23

regen lockfile

4ee1283

fix snapshots

cbbeac0

sync esbuild versions

6f81144

give errors an explicit name property, that cannot be compiled away

1504c34

ndelangen added 2 commits November 12, 2025 15:19

fix

5176096

Merge branch 'next' into minify-syntax

50d8e1c

ndelangen requested a review from shilman November 12, 2025 14:24

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Update @storybook/icons dependency to version 2.0.0 across multiple p…

0d98abb

…ackages

ndelangen merged commit b13be59 into storybookjs:next Nov 13, 2025
73 checks passed

github-actions bot mentioned this pull request Nov 13, 2025

Release: Prerelease 10.1.0-alpha.11 #33032

Merged

7 tasks

mrginglymus deleted the minify-syntax branch November 13, 2025 10:33

ndelangen added the needs qa Indicates that this needs manual QA during the upcoming minor/major release label Nov 21, 2025

yannbf removed the needs qa Indicates that this needs manual QA during the upcoming minor/major release label Nov 25, 2025

coderabbitai bot mentioned this pull request Dec 8, 2025

Addon-Vitest: Isolate error reasons during postinstall #33295

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coderabbitai bot mentioned this pull request Dec 20, 2025

[Bug]: crashes with browserslist baseline queries #33401

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Maintenance: Enable syntax minification for dead code elimination #33001

Maintenance: Enable syntax minification for dead code elimination #33001

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mrginglymus commented Nov 11, 2025 • edited by ndelangen Loading Uh oh! There was an error while loading. Please reload this page.

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What I did

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

Manual testing

Documentation

Checklist for Maintainers

🦋 Canary release

Summary by CodeRabbit

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Package Benchmarks

@storybook/addon-a11y

@storybook/addon-vitest

@storybook/builder-vite

@storybook/builder-webpack5

storybook

@storybook/angular

@storybook/ember

@storybook/html-vite

@storybook/nextjs

@storybook/nextjs-vite

@storybook/preact-vite

@storybook/react-native-web-vite

@storybook/react-vite

@storybook/react-webpack5

@storybook/server-webpack5

@storybook/svelte-vite

@storybook/sveltekit

@storybook/vue3-vite

@storybook/web-components-vite

@storybook/cli

@storybook/codemod

create-storybook

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mrginglymus commented Nov 11, 2025 •

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`@storybook/addon-a11y`

`@storybook/addon-vitest`

`@storybook/builder-vite`

`@storybook/builder-webpack5`

`storybook`

`@storybook/angular`

`@storybook/ember`

`@storybook/html-vite`

`@storybook/nextjs`

`@storybook/nextjs-vite`

`@storybook/preact-vite`

`@storybook/react-native-web-vite`

`@storybook/react-vite`

`@storybook/react-webpack5`

`@storybook/server-webpack5`

`@storybook/svelte-vite`

`@storybook/sveltekit`

`@storybook/vue3-vite`

`@storybook/web-components-vite`

`@storybook/cli`

`@storybook/codemod`

`create-storybook`