## Summary
- Adds `Bun.JSON5.parse()` and `Bun.JSON5.stringify()` as built-in APIs
- Adds `.json5` file support in the module resolver and bundler
- Parser uses a scanner/parser split architecture with a labeled switch
pattern (like the YAML parser) — the scanner produces typed tokens, the
parser never touches source bytes directly
- 430+ tests covering the official JSON5 test suite, escape sequences,
numbers, comments, whitespace (including all Unicode whitespace types),
unquoted/reserved-word keys, unicode identifiers, deeply nested
structures, garbage input, error messages, and stringify behavior
<img width="659" height="610" alt="Screenshot 2026-01-25 at 12 19 57 AM"
src="https://github.com/user-attachments/assets/e300125a-f197-4cad-90ed-e867b6232a01"
/>
## Test plan
- [x] `bun bd test test/js/bun/json5/json5.test.ts` — 317 tests
- [x] `bun bd test test/js/bun/json5/json5-test-suite.test.ts` — 113
tests from the official JSON5 test suite
- [x] `bun bd test test/js/bun/resolve/json5/json5.test.js` — .json5
module resolution
closes#3175🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
## Summary
- Fixes strings ending with colons (e.g., `"tin:"`) not being quoted in
YAML.stringify output
- This caused YAML.parse to fail with "Unexpected token" when parsing
the output back
## Test plan
- Added regression tests in `test/regression/issue/25439.test.ts`
- Verified round-trip works for various strings ending with colons
- Ran existing YAML tests to ensure no regressions
Fixes#25439🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
### What does this PR do?
Fixes ENG-21490
### How did you verify your code works?
Added a test that would previously fail due to timeout. It also confirms
the parsed result is correct.
---------
Co-authored-by: taylor.fish <contact@taylor.fish>
### What does this PR do?
Ensures strings that would parse as a number with leading zeroes aren't
emitted without quotes.
fixes#23691
### How did you verify your code works?
Added a test
### What does this PR do?
Fixes#23489
The YAML parser was incorrectly treating `...` inside double-quoted
strings as document end markers, causing parse errors for strings
containing ellipsis, particularly affecting internationalized text.
### Example of the bug:
```yaml
balance: "👛 لا تمتلك محفظة... !"
```
This would fail with: `error: Unexpected document end`
### Root cause:
The bug was introduced in commit fcbd57ac48 which attempted to optimize
document marker detection by using `self.line_indent == .none` instead
of tracking newlines with a local flag. However, this check was
incomplete - it didn't track whether we had just processed a newline
character.
### The fix:
Restored the `nl` (newline) flag pattern from the single-quoted scanner
and combined it with the `line_indent` check. Document markers `...` and
`---` are now only recognized when **all** of these conditions are met:
1. We're after a newline (`nl == true`)
2. We're at column 0 (`self.line_indent == .none`)
3. Followed by whitespace or EOF
This allows `...` to appear freely in double-quoted strings while still
correctly recognizing actual document end markers at the start of lines.
### How did you verify your code works?
1. Reproduced the original issue from #23489
2. Applied the fix and verified all test cases pass:
- Original Arabic text with emoji: `"👛 لا تمتلك محفظة... !"`
- Various `...` positions: start, middle, end
- Both single and double quotes
- Multiline strings with indented `...` (issue #22392)
3. Created regression test in `test/regression/issue/23489.test.ts`
4. Verified existing YAML tests still pass (514 pass, up from 513)
cc @dylan-conway for review
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
Co-authored-by: Dylan Conway <dylan.conway567@gmail.com>
### What does this PR do?
Makes sure strings are doubled quoted when they start with flow
indicators and `:`.
Fixes#23502
### How did you verify your code works?
Added tests for each indicator in flow and block context
### What does this PR do?
Adds `expect().toBe()` checks for anchors/aliases. Also adds git commit
the tests were translated from.
### How did you verify your code works?
Manually
### What does this PR do?
Fixes bugs in the parser bringing it to 90% passing the official
[yaml-test-suite](https://github.com/yaml/yaml-test-suite) (362/400
passing tests)
Still missing from our parser: |- and |+ (about 5%), and cyclic
references.
Translates the yaml-test-suite to our tests.
fixes#22659fixes#22392fixes#22286
### How did you verify your code works?
Added tests for yaml-test-suite and each of the linked issues
---------
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
### What does this PR do?
This PR adds `Bun.YAML.stringify`. The stringifier will double quote
strings only when necessary (looks for keywords, numbers, or containing
non-printable or escaped characters). Anchors and aliases are detected
by object equality, and anchor name is chosen from property name, array
item, or the root collection.
```js
import { YAML } from "bun"
YAML.stringify(null) // null
YAML.stringify("hello YAML"); // "hello YAML"
YAML.stringify("123.456"); // "\"123.456\""
// anchors and aliases
const userInfo = { name: "bun" };
const obj = { user1: { userInfo }, user2: { userInfo } };
YAML.stringify(obj, null, 2);
// # output
// user1:
// userInfo:
// &userInfo
// name: bun
// user2:
// userInfo:
// *userInfo
// will handle cycles
const obj = {};
obj.cycle = obj;
YAML.stringify(obj, null, 2);
// # output
// &root
// cycle:
// *root
// default no space
const obj = { one: { two: "three" } };
YAML.stringify(obj);
// # output
// {one: {two: three}}
```
### How did you verify your code works?
Added tests for basic use and edgecases
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
- New Features
- Added YAML.stringify to the YAML API, producing YAML from JavaScript
values with quoting, anchors, and indentation support.
- Improvements
- YAML.parse now accepts a wider range of inputs, including Buffer,
ArrayBuffer, TypedArrays, DataView, Blob/File, and SharedArrayBuffer,
with better error propagation and stack protection.
- Tests
- Extensive new tests for YAML.parse and YAML.stringify across data
types, edge cases, anchors/aliases, deep nesting, and round-trip
scenarios.
- Chores
- Added a YAML stringify benchmark script covering multiple libraries
and data shapes.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
---------
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>
### What does this PR do?
fixes parsing strings like `"1e18495d9d7f6b41135e5ee828ef538dc94f9be4"`
### How did you verify your code works?
added a test.
### What does this PR do?
This PR adds builtin YAML parsing with `Bun.YAML.parse`
```js
import { YAML } from "bun";
const items = YAML.parse("- item1");
console.log(items); // [ "item1" ]
```
Also YAML imports work just like JSON and TOML imports
```js
import pkg from "./package.yaml"
console.log({ pkg }); // { pkg: { name: "pkg", version: "1.1.1" } }
```
### How did you verify your code works?
Added some tests for YAML imports and parsed values.
---------
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>
