## Summary
- Removes unused function and class expression names when
`--minify-syntax` is enabled during bundling
- Adds `--keep-names` flag to preserve original names when minifying
- Matches esbuild's minification behavior
## Problem
When minifying with `--minify-syntax`, Bun was keeping function and
class expression names even when they were never referenced, resulting
in larger bundle sizes compared to esbuild.
**Before:**
```js
export var AB = function A() { };
// Bun output: var AB = function A() {};
// esbuild output: var AB = function() {};
```
## Solution
This PR adds logic to remove unused function and class expression names
during minification, matching esbuild's behavior. Names are only removed
when:
- `--minify-syntax` is enabled
- Bundling is enabled (not transform-only mode)
- The scope doesn't contain direct eval (which could reference the name
dynamically)
- The symbol's usage count is 0
Additionally, a `--keep-names` flag has been added to preserve original
names when desired (useful for debugging or runtime reflection).
## Testing
- Updated existing test in `bundler_minify.test.ts`
- All transpiler tests pass
- Manually verified output matches esbuild for various cases
## Examples
```bash
# Without --keep-names (names removed)
bun build --minify-syntax input.js
# var AB = function() {}
# With --keep-names (names preserved)
bun build --minify-syntax --keep-names input.js
# var AB = function A() {}
```
🤖 Generated with [Claude Code](https://claude.ai/code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Dylan Conway <dylan.conway567@gmail.com>
### What does this PR do?
### How did you verify your code works?
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Tests**
* Enabled multiple previously skipped bundler and esbuild test cases by
removing todo flags, increasing test suite coverage.
* Broadened cross-platform applicability by removing OS-specific gating
in certain tests, ensuring they run consistently across environments.
* Activated additional scenarios around resolve/load behavior, dead code
elimination, package.json handling, and extra edge cases.
* No impact on runtime behavior or public APIs; changes are limited to
test execution and reliability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
---------
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
* random acts of cleanup to tests
* nerf the watchFile test, is CI slow?
* more things
* [autofix.ci] apply automated fixes
* a
* remove a log
---------
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
* work on bundler
* a
* YAAAAYYAYAYAYYAYA
* get some more bundler tests working
* Update src/bundler/bundle_v2.zig
* rev
* ok
* i converted the cmakelists into LF
* personal review
* we didnt win
* okey they pass
* revert :(
* a
---------
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
* fix(win/upgrade): do not show powershell expand-archive info while upgrading
* start working bun run
* experiment: `bun.new`
* you can now bun run
* Update src/install/install.zig
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
* Update src/install/install.zig
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
* stuff
* fix stuff
* fix this
* farther but not really
* sadfs
* path hell
not sure how much worse or better this makes things. its a mess. windows path handlign is a mess aaaaaaaaaaaaaaaa
* path.resolve bs
* remove old build system stuff from pr
* a
* fix some path.parse/join cases
* path closer not perfect
* normalize and join tests tests done
* paths
* implement path.relative
* ,
* stuff
* assert
* fix compile
* hate
* the code isnt great
* stuff
* housekeeping for build system
* blah
* explain windows sitaution in docs
* some progress? not much though
* zig compiler crashes here
* fix
* yippee
* ok
* a
* ala wala
* fix builds on stuff
* clean
* the tests now run
* a
* aa
* dedupe uv event loop
* fix fs test accuracy
* stuff
* [autofix.ci] apply automated fixes
* huge updat e
* [autofix.ci] apply automated fixes
* url
* [autofix.ci] apply automated fixes
* start windows spawnSync
* [autofix.ci] apply automated fixes
* add --webkit for update submodules
* add better err message for `bun setup`
* fix unix platform build
* .
* [autofix.ci] apply automated fixes
* un-upgrade libarchive
* z
* asdfghj
* wrk
* todo -> panic
* ok
* a
* [autofix.ci] apply automated fixes
* fix build scripts l ol
* dfghj
* fa
* [autofix.ci] apply automated fixes
* aaaa
* a
* l
* [autofix.ci] apply automated fixes
* more logs
* [autofix.ci] apply automated fixes
* j
* fix init_command
* CORE DUMP HELL
* i swear im being pranked by the github actions gods
* fadsjkfdshjkhjkdfsahjkdfshjksdafjkhhjkfdsahfsdkjhfsdjkahf
* thanks IAS
* this is the correct fix
* personal review
* ddisablbe these
* revisions!
* ok
* fix submodule
* stuff
* fix libarchive
* [autofix.ci] apply automated fixes
* stuff
* [autofix.ci] apply automated fixes
* a
* fix addressToJS on windows
* make dns async again
* dx: add flag to update submodules ps1 to clone webkit
* dns error case for libuv
* dx improvements on windows
* newline
* obvious fix
* install steps
* extra note
* fix fs test
* Update building-windows.md
* fix builtins bundler to support \r\n line endnigs
* better
* some windows stuff
* a
* a
* a
* aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
* [autofix.ci] apply automated fixes
* bunfile text works
* fix build on the mac
* hellooooooooooo
* install steps
* ci for baseline?
* fix
* aaa
* wow
* install script revamp
* bug
* OK
* ok
* aaaaaaaaaaaaaa
* okay
* fix the node test runner lol
* fix napi stuff
---------
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: cirospaciari <ciro.spaciai@gmail.com>
Co-authored-by: Dylan Conway <35280289+dylan-conway@users.noreply.github.com>
* feat(console-log): fix className not printed for objects that are instances of classes
Uses getClassName native method instead of getName
* test(console-log): objects with class names are printed correctly
* test(esbuild): add class name to log message
* Fix missing function names in Bun.inspect
* Fix failing tests
* Handle @@toStringTag
* Update bindings.cpp
* Revert breaking changes to snapshots until a minor version
* Fix test
---------
Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>
* wip changes for CommonJS
* this rewrite is almost complete
* even more code
* wip
* Remove usages of `import.meta.require` from builtins
* Remove usages of require
* Regenerate
* ✂️ builtin rewrite commonjs in printer
* Use lazy custom getters for import.meta
* fixups
* Remove depd
* ugh
* still crashing
* fixup undici
* comment out import.meta.require.resolve temporarily
not a real solution but it stops the crashes
* Redo import.meta.primordials
* Builtins now have a `builtin://` protocol in source origin
* Seems to work?
* Finsih getting rid of primordials
* switcharoo
* No more function
* just one more bug
* Update launch.json
* Implement `require.main`
* ✂️
* Bump WebKit
* Fixup import cycles
* Fixup improt cycles
* export more things
* Implement `createCommonJSModule` builtin
* More exports
* regenerate
* i broke some stuff
* some of these tests work now
* We lost the encoding
* Sort of fix zlib
* Sort of fix util
* Update events.js
* bump
* bump
* bump
* Fix missing export in fs
* fix some bugs with builtin esm modules (stream, worker_threads, events). its not perfect yet.
* fix some other internal module bugs
* oops
* fix some extra require default stuff
* uncomment this file but it crsahes on my machine
* tidy code here
* fixup tls exports
* make simdutf happier
* Add hasPrefix binding
* Add test for `require.main`
* Fix CommonJS evaluation order race condition
* Make node:http load faster
* Add missing exports to tls.js
* Use the getter
* Regenerate builtins
* Fix assertion failure in Bun.write()
* revamp dotEnv parser (#3347)
- fixes `strings.indexOfAny()`
- fixes OOB array access
fixes#411fixes#2823fixes#3042
* fix tests for `expect()` (#3384)
- extend test job time-out for `darwin-aarch64`
* `expect().resolves` and `expect().rejects` (#3318)
* Move expect and snapshots to their own files
* expect().resolves and expect().rejects
* Fix promise being added to unhandled rejection list
* Handle timeouts in expect(<promise>)
* wip merge
* Fix merge issue
---------
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>
* fixup min/memcopy (#3388)
* Fix crash in builtins
* Don't attempt to evaluate modules with no source code
* Update WebCoreJSBuiltins.cpp
* Update WebCoreJSBuiltins.cpp
* Update WebCoreJSBuiltins.cpp
* Fix crash
* cleanup
* Fix test
cc @paperdave
* Fixup Undici
* Fix issue in node:http
* Create util-deprecate.mjs
* Fix several bugs
* Use the identifier
* Support error.code in `util.deprecate`
* make the CJs loader slightly more resilient
* Update WebCoreJSBuiltins.cpp
* Fix macros
---------
Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>
Co-authored-by: dave caruso <me@paperdave.net>
Co-authored-by: Alex Lam S.L <alexlamsl@gmail.com>
Co-authored-by: Ashcon Partovi <ashcon@partovi.net>
Co-authored-by: Ciro Spaciari <ciro.spaciari@gmail.com>
* start this
* commit
* mark all failing tests as todo
* fasdfad
* bundler tests
* tests
* adjust failing tests to todo
* comment out some more tests
* png as test
* handle multiple output files and `[dir]`
* get the realpath of `root_dir`
* duplicate output paths
* add `rootdir` to `JSBundler`
* use realpath of input file
* add tests for naming and root
---------
Co-authored-by: Dave Caruso <me@paperdave.net>
* parse error logs
* clean up types
* remove --jsx-production. use NODE_ENV instead
* add define to js api
* add loaders to js api
* fixups
* sourcemap
* typo fix
* remove label, comment dir just for now
* test tweaks
* test work
* make optional enums actually optional.
allows `sourcemap: undefined`
* overload host ram test
* string tests
* tests
* test for 2815
* requested changes
* sort this list
* remove this test file now that it passes
* oops
* add --format
* finish ts tests
* doc typos related to define and loader
* start refine + skipping some packagejson tests
* some more tests
* stuff
* tests for minify branch
* pkgjson
* add minify/MergeAdjacentVars
* add test for #2699
* more tests!
* more tests
* finish splitting tests
* all but 2 import star tests are good
* test
* Fix `make dev` reusing old .o file
* more bundler tests
* document capture
* bundler tests
* bundler tests
* bundler tests
* finish up
* remove bad thing to merge on main
* alright now just gotta try running it
* fix a gajillion compiler errors
* even more code
* okay i fixed more errors
* wip
* Update launch.json
* Update string_builder.zig
* `fast_debug_build_mode` makes debug build 2x faster
* Update bundle_v2.zig
* more code!
* It bundles!
* Rename `Bun.Transpiler` to `Bun.Bundler`
* `import()` expressions almost work
* wip attempt to get import() expr to work
* Bundle namespace imports
* Attempt to fix the issue with import() unsuccessfully
* consider current working directory when resolving relative paths (#2313)
* consider current working directory when resolving relative paths
fixes#2298
* comment test
---------
Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>
* support `expect().toThrow(/pattern/)` (#2314)
- fix time-zone-dependent test failure
* fix missing `Blob` error messages on Linux (#2315)
* fix & clean up tests (#2318)
- skip flaky tests when running as `root`
- use `expect().toThrow()`
- clean up temporary files after tests
* feat(tty): add some `tty.WriteStream` methods to `process.{stdout, stderr}` (#2320)
* feat(stdio): add some `tty.WriteStream` methods
* chore(builtins): add process builtin gen'd code
* Fix docker install command
* `bun test` on macOS in GitHub Actions (#2322)
* Fixes#2323
* throw invalid parameter errors in `crypto.scryptSync` (#2331)
* throw invalid parameter errors
* remove comptime, add empty buffer function
* remove error_name comptime
* Add reference documentation for bun:test (#2327)
* Reorganize tests (#2332)
* Fix html-rewriter.test.js
* fix the wrong thing being incremented in hmr example (#2334)
* Add more test harness
* Improve Benchmarking page, small fixes (#2339)
* Improve benchmarking page
* WIP
* Add typescript instructions to hot
* Document preload in Plugins. Fix loader in plugin types.
* Fix typo
* Fix links
* run prettier
* Document openInEditor
* improve `Buffer` compatibility with Node.js (#2341)
* improve `Buffer` compatibility with Node.js
* use `memmove()`
allow `encoding` to be `undefined`
* run `bun test` after macOS builds (#2343)
* "binary" is an alias of "latin1"
Fixes https://github.com/oven-sh/bun/issues/2110
* More spec compliant `Blob.prototype.type` (#2340)
* Make `Blob.prototype. type` more spec compliant
* Add a few more checks for isNumber()
* Fix `make headers`
* Safer JSValue.isString()
* More tests for blob.slice
* Make `Blob.prototype.type` more spec compliant
* Add isASCII check
* Fix types
* Fix failing type test
* Update blob.zig
* Update blob.zig
* Fix .eql check on empty values
---------
Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>
* Fix bug in test runner
* Support `import()` expressions
* Implement `require()`
* clean up bit_set.zig slightly
* Move some things around
* misc cleanup
* Cleanup some things
* Fix a lot of stuff
* Fix `module.exports.fn = fn;` in ESM entry point
* Fix crash due when printing file
* Fix issue with class names
* Fix issue with `export default identifier`
* Update js_parser.zig
* optimization: inline single-property object acceses and arrays
* Fix undefined memory in renamed symbols list
* Handle call target
* wip
* Inline it
* Fix undefined memory issue when reclaiming blocks in ast
* Halt linking on any parse errors
* alias
* Rename `enable_bundling` to `enable_legacy_bundling`
* Workaround anonymous struct literal zig bug
* Use slower approach (without bitset) because it doesn't break after 8 symbols
* Fix incorrectly-renaming statically defined symbols
* Handle more edgecases in our bit_set fork
* Reduce number of allocations for `define`
* Do not rename unbound symbols
* Clean up dot defines a little more
* Make the generated names prettier
* Workaround runtime symbol missing issue
* Fail the build on errors
* Support export * from
* Support `--outfile`
* partially fix renaming
* fanicer symbol renaming impl
* misc, extremely revertible cleanup
* Fix up some bugs with symbol renaming
* formatting
* Update launch.json
* Parse `__PURE__` comments
* clean up simd code for pure comments
* changes to merge
* workaround runtime issue
* Fix issue with `export * as` not propagating correctly
* Make all top-level declarations `var` when bundling
* Fix missing prefix
* Fix assigning to stack copy
* Fix missing runtime symbol
* Fix bug with namespace exports
* Dramatically reduce allocations
* Update launch.json
* Add missing flags
* Update js_parser.zig
* small cleanup
* Make the export name better
* Fix unnecessary `var foo = foo`
* Implement CommonJS -> ESM conversion
* Implement module redirects
* Port esbuild bundler tests for new bundler (#2380)
* started porting esbuild tests
* clean up test names and api before moving on
* port tests using a program i wrote
* replace todo generated comment
* fix generated tests not including some files
* work on tests
* [github web editor] add define, external, inject, minifySyntax, minifyWhitespace options.
* get most of the todo comments out of the way, but expectBundled does not handle most of the cases
* continue working on esbuild tests
* use test.skip for unsupported tests
* Fixups for test runner
* Hoist imports & exports
* Fix test
* Hoist classes
* bundler test refining, 51/835
* Fix runtime require
* bundler test refining, 81/835
* bundler test refining, 93/835
* Make the test work in any timezone
* feat(expect): update toBeInstanceOf (#2396)
* feat: update instanceof binding
* fix: according to PR comments
* Rename `expectObjectTypeCount` to `expectMaxObjectTypeCount`
* Fix socket tests with connection errors (#2403)
* release pending activity with connection error handler
* unref poll_ref
* remove trailing comma
* Organize Dockerfiles for official status
* Remove test Dockerfile
* Remove old Docker workflow
* Feat(test): add toMatch (#2404)
* Fix various fetch/response/request tests (#2416)
* fix most fetch tests, skip a few
* fastGet, toValueGC, and invalid init
* bigint unreachable, range error, log process as process
* remove extra fetch_headers
* remove js_type parameter, check isObject()
* throw invalid mime type error, use enum literal
* switch back to promise rejection
* RangeError pascal case
* Fix several bugs (#2418)
* utf16 codepoint with replacement character
* Fix test failure with `TextEncoder("ascii')`
* Add missing type
* Fix Response.prototype.bodyUsed and Request.prototype.bodyUsed
* Fix bug with scrypt error not clearing
* Update server.zig
* oopsie
* 💅
* docs: Use correct url in the 'Issues' link in README header (#2420)
* Fix crash when rendering error page and the server or network is slow
* [fetch] Make the default body value `null` when unspecified
This is better aligned with the fetch spec
* Make node-net tests less flaky
* [node:net] Fix issue with `listen` callback firing before it's listening
* Always clear timers in node test harness
* Fix out of bounds access
Repro'd in Buffer tests
* Update UWS
cc @cirospaciari
* Make this test more thorough
* Hanging abort test
* 0 length body is a null stream
* Several bug fixes (#2427)
* Fix test
* Fix segfault when unexpected type is passed in `expect().toThrow`
* Fix issues with request constructor
* Don't bother cloning headers when its empty
* woops
* more tests
* fix incorrect test
* Make the fetch error messages better
* Update response.zig
* Fix test that failed on macOS
* Fix test
* Remove extra hash table lookups
* Support running dummy registry directly
cc @alexlamsl
* Update test
* Update test
* fixup
* Workaround crash in test runner
* Fixup test
* Fixup test
* Update os.test.js
---------
Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>
* Remove usages of port numbers in tests
* Set -O2 and -fno-rtti
* Remove -g
* Prevent undefined memory access
* [bun test] Implement `--rerun-each` flag to run each test N times
* Reduce number of module scopes created
* add some extra abort checks into streams (#2430)
* add some checks to avoid UAF
* avoid multiple calls to finalize if endFromJS is called more than once
* fix no-op comment
* mark as requested_end on abort
* remove requested_end from abort
* remove unnecessary check (#2432)
* Fix bug with scoped aliased dependencies in bun install on macOS
* remove `addLog`, remove `--prominent-compile-errors`
* Finish the upgrade
* Optional chaining flag
* Implement same_target_becomes_destructuring optimization
* bundler test refining, 109/835
* Reset bindings
* Support multiple entry points
* Implement `--entry-names` flag
* Use a tempdir with a better name
* prettier
* Log file name
* Update js_parser.zig
* Mark all bun builtins as external
* Make resolve errors actually errors
* Update bundler_default.test.ts
* Fix `await import(foo)`
* WIP react server components
* Do more stuff at runtime
* ✂️
* Support automatic JSX imports
* Use a module cache for now
* Update tsconfig.base.json
* Fix ThisOutsideFunctionNotRenamed
* woopsie
* moar cpu
* clamp it
* fixup
* Add a bunch of assertions
* Bun uses automatic runtime by default
* Parse Import Attributes
* Add a note about Valgrind
* Update developing.md
* Fix up code splitting for React Server Components
* Implement client component manifest
* Fix crash with --react-server-components and no client components
* Backport 4d31e3c917
* Update launch.json
* Fix for latest zig
* Workaround bug with ?[]const string
Occasionally saw alignment errors in this code
Workaround https://github.com/ziglang/zig/issues/15085
related: https://github.com/ziglang/zig/pull/15089
* switch to regular slice
* Avoid initializing named_imports and named_exports as undefined
* Reduce usages of `undefined`
* Add more assertions
* --watch wip
* Update javascript.zig
* Possibly fix the race condition
* Faster `do`
* bump allocator
* Reduce the size of `Symbol` slightly
* Alphabetically sort runtime import symbols, for determinism
* Prepare for code splitting
* handle overlapping stdout
* pure
* clean up some things
* Fix bug with `$$typeof`
* Address CommonJS -> ESM hoisting bug
* Support `"use server"` in manifest
* Implement `"use server"`
* Fix importing bun builtins when bundling
* Make `commonjs_to_esm` a feature flag, fix some splitting bugs
* ✂️
* fixme remove this
* Fix crash in longestCommonPath
* Chunking! Just need to do import paths now.
* Import paths work...now trying to figure out how to make runtime symbols work
* add workaround
* Replace `bun bun` with `bun build`
* Fix crash with dual package hazard
* Fix many CommonJS <> ESM interop bugs
* Support package.json `"sideEffects"`
also skip loading unnecessary package.json data in `bun run`
* add a not good --watch implementation
* bundler test refining, 140/831
* remove accidentally committed file
* do not return status code 1 on successful bundles
* bundler test refining, 159/830
* pass exit code to exitOrWatch
* clean up help menu
-remove two spaces to line up bun build
-moved all <r> tags to the end of the text they are colorizing
-moved other colors to the start of the text they colorize
-removed unneeded <r> tags, keeping only one at the start of the block
* importstar is fully ported
* wip
* you can run code in this branch now
* Disable this transform
* organize and document bundler tests
* Fix double import
* Fix sloppy mode function declarations
* Disable our CommonJS transform for now
* add `assertNotPresent` to make splitting cases easier
* Bump!
* Update bun.d.ts
* use import.meta.require in runtime code
* Disable this again
* Fix dirname
* Fix ESM -> CJS wrapper
* 💅
---------
Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>
Co-authored-by: Alex Lam S.L <alexlamsl@gmail.com>
Co-authored-by: Derrick Farris <mr.dcfarris@gmail.com>
Co-authored-by: Ashcon Partovi <ashcon@partovi.net>
Co-authored-by: Dylan Conway <35280289+dylan-conway@users.noreply.github.com>
Co-authored-by: pfg <pfg@pfg.pw>
Co-authored-by: Colin McDonnell <colinmcd94@gmail.com>
Co-authored-by: dave caruso <me@paperdave.net>
Co-authored-by: zhiyuan <32867472+zhiyuang@users.noreply.github.com>
Co-authored-by: Dylan Conway <dylan.conway567@gmail.com>
Co-authored-by: Kamil Ogórek <kamil.ogorek@gmail.com>
Co-authored-by: Ciro Spaciari <ciro.spaciari@gmail.com>
