### What does this PR do?
Fixes#5344Fixes#6356
### How did you verify your code works?
Some test coverage
---------
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Claude Bot <claude-bot@bun.sh>
### What does this PR do?
This branch:
> Ran 1600 tests across 46 files. [63.24s]
Main:
> Ran 1600 tests across 46 files. [137.05s]
This makes the bundler tests run about 60 seconds faster
### How did you verify your code works?
## 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>
## Summary
Implements the `typeof undefined === 'u'` minification optimization from
esbuild in Bun's minifier, and fixes dead code elimination (DCE) for
typeof comparisons with string literals.
### Part 1: Minification Optimization
This optimization transforms:
- `typeof x === "undefined"` → `typeof x > "u"`
- `typeof x !== "undefined"` → `typeof x < "u"`
- `typeof x == "undefined"` → `typeof x > "u"`
- `typeof x != "undefined"` → `typeof x < "u"`
Also handles flipped operands (`"undefined" === typeof x`).
### Part 2: DCE Fix for Typeof Comparisons
Fixed dead code elimination to properly handle typeof comparisons with
strings (e.g., `typeof x <= 'u'`). These patterns can now be correctly
eliminated when they reference unbound identifiers that would throw
ReferenceErrors.
## Before/After
### Minification
Before:
```javascript
console.log(typeof x === "undefined");
```
After:
```javascript
console.log(typeof x > "u");
```
### Dead Code Elimination
Before (incorrectly kept):
```javascript
var REMOVE_1 = typeof x <= 'u' ? x : null;
```
After (correctly eliminated):
```javascript
// removed
```
## Implementation
### Minification
- Added `tryOptimizeTypeofUndefined` function in
`src/ast/visitBinaryExpression.zig`
- Handles all 4 equality operators and both operand orders
- Only optimizes when both sides match the expected pattern (typeof
expression + "undefined" string)
- Replaces "undefined" with "u" and changes operators to `>` (for
equality) or `<` (for inequality)
### DCE Improvements
- Extended `isSideEffectFreeUnboundIdentifierRef` in `src/ast/P.zig` to
handle comparison operators (`<`, `>`, `<=`, `>=`)
- Added comparison operators to `simplifyUnusedExpr` in
`src/ast/SideEffects.zig`
- Now correctly identifies when typeof comparisons guard against
undefined references
## Test Plan
✅ Added comprehensive test in `test/bundler/bundler_minify.test.ts` that
verifies:
- All 8 variations work correctly (4 operators × 2 operand orders)
- Cases that shouldn't be optimized are left unchanged
- Matches esbuild's behavior exactly using inline snapshots
✅ DCE test `dce/DCETypeOfCompareStringGuardCondition` now passes:
- Correctly eliminates dead code with typeof comparison patterns
- Maintains compatibility with esbuild's DCE behavior
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
---------
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: Jarred Sumner <jarred@jarredsumner.com>
Co-authored-by: Dylan Conway <dylan.conway567@gmail.com>
### What does this PR do?
Originally, we attempted to avoid the "dual package hazard" right before
we enqueue a parse task, but that code gets called in a
non-deterministic order. This meant that some of your modules would use
the right variant and some of them would not.
We have to instead do that in a separate pass, after all the files are
parsed.
The thing to watch out for with this PR is how it impacts the dev
server.
### How did you verify your code works?
Unskipped tests. Plus manual.
---------
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Dylan Conway <dylan.conway567@gmail.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.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>
* feat(options): add possibility to append a custom esm condition
* feat(cli): parse --conditions flag
* test: add case for custom conditions
* fix(cli): not get short-hand --conditions flag
* test: add case using cjs with custom condition
* fix(options): address possible memory issues for esm conditions
* refactor(cli): remove -c alias for --conditions flag
* test: add cases for multiple --conditions specified
* test(bundler): add support to test --conditions
* chore(cli): fix grammar mistakes in --conditions
---------
Co-authored-by: Jarred Sumner <jarred@jarredsumner.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>
* get test/bundler/bundler_naming.test.ts passing on windows
* move platformToPosixInPlace to bun.path and use the vector'd version
* only resolve rel_path if it contains '/./', most of the time './' needs to be preserved
* fix another file too
* move kernel32 extern to better location
* [autofix.ci] apply automated fixes
* use bun.path.posixToPlatformInPlace here
* rewrite this whole section to stay in utf16 and handle errors
* remove dead comments
* fix a typo
* undo these relative changes
* preserve path.pretty from getting lost
* use bun's instead of zig's resolve here
* both side of this loop need the inplace normal
* use existing generic dirname function
* make path inplace functions generic
* we might need to modify this so copy on windows
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
* don't assume the prefix we get from this
* more robust path traversal
* don't mangle absolute paths
* do this bit in a loop
* this line is a u16
* dont forget to compile before pushing
* this was wrong
* look into this later
* check pointer math first since its faster
* posix syscalls support path traversal, don't do the work for them
* its already inside stable, no need to change
* used the online editor
---------
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
