fix(handlers): parse all three modulate args (brightness, saturation, hue)

[dev48v]

🔗 Linked issue

Fixes #301

📚 Description

The modulate handler declared args: [VArg], so parseArgs only pulled the first value out of the URL segment. Its apply takes three (brightness, saturation, hue), so saturation and hue were always undefined.

A request like /_ipx/modulate_2_1_1/example.png then failed with:

[IPX_ERROR] Expected number above zero for saturation but received undefined of type undefined

Fix: declare all three arg mappers — args: [VArg, VArg, VArg] — matching the sibling multi-arg handlers, so every value is parsed and forwarded to sharp. One-line change plus a regression test.

Thanks to @wuiyang for pinpointing the exact location (src/handlers/handlers.ts).

✅ Test

Added a test that drives the handler through applyHandler (i.e. through parseArgs, not apply() directly) so it covers the arg-count contract:

modulate parses all three args (brightness, saturation, hue) (#301)

• vitest run test/handlers/handlers.test.ts → 53 passed (incl. the new test)
• eslint . → clean

The existing modulate.apply() returns expected values test called apply() with three args directly, so it didn't exercise the parsing gap; the new test does.

Summary by CodeRabbit

• Bug Fixes

  • Fixed the image modulation command so it now correctly accepts brightness, saturation, and hue values together.
  • Improved handling of modulation inputs so the applied settings match the values provided.

• Tests

  • Added coverage for modulation input parsing and verified the expected image adjustment values are passed through.

[coderabbitai]

📝 Walkthrough

Walkthrough

The modulate handler's args declaration was changed from a single VArg to three VArg entries, aligning it with its apply function that consumes brightness, saturation, and hue. A corresponding test was added using applyHandler to verify correct parsing of delimited argument strings.

Changes

Modulate args fix

Layer / File(s)	Summary
Handler args contract and test src/handlers/handlers.ts, test/handlers/handlers.test.ts	modulate's Handler declaration now expects three VArg entries instead of one, matching its apply function; a new test uses applyHandler to confirm "2_1_1" parses into { brightness: 2, saturation: 1, hue: 1 }.

Estimated code review effort: 1 (Trivial) | ~5 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The changes address issue #301 by parsing and forwarding all three modulate args and adding regression coverage.
Out of Scope Changes check	✅ Passed	The diff stays focused on the modulate argument parsing fix and its test coverage.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: fixing modulate to parse all three arguments.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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