feat: add unflatten handler

[nathanchase]

This pull request introduces a new handler function to the src/handlers/handlers.ts file. The new function, unflatten, is experimental and its API may change in the future.

New handler function added:

• src/handlers/handlers.ts: Added the unflatten handler, which calls the unflatten method on the provided pipe. This feature is marked as experimental.

See https://sharp.pixelplumbing.com/api-operation#unflatten for more information.

Summary by CodeRabbit

• New Features

  • Added an unflatten image-processing operation, including support as a modifier option, to help restore image data that was previously flattened.

• Documentation

  • Updated the “Modifiers” table formatting in the README (whitespace/alignment tweaks) so the table renders cleanly and remains properly aligned.

[pi0]

Thanks for PR dear @nathanchase. Wondering is it worth to wait for sharp feature to be stable first?

Do you have some more context why it is in experimental state?

[codecov]

Codecov Report

❌ Patch coverage is 33.33333% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 74.69%. Comparing base (70acd53) to head (1ba36ef).

Files with missing lines	Patch %	Lines
src/handlers/handlers.ts	33.33%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #248      +/-   ##
==========================================
- Coverage   75.00%   74.69%   -0.31%     
==========================================
  Files           8        8              
  Lines         412      415       +3     
  Branches      109      109              
==========================================
+ Hits          309      310       +1     
- Misses         85       87       +2     
  Partials       18       18              

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[nathanchase]

Thanks for PR dear @nathanchase. Wondering is it worth to wait for sharp feature to be stable first?

Do you have some more context why it is in experimental state?

I don't have any knowledge of why it's experimental. I just know that I have an immediate use case for it with https://github.com/nuxt/image to make all images with a solid white background become transparent backgrounds. I happened to notice it wasn't wired up to sharp's implementation, so this was just meant as a means of connecting to the unflatten functionality that already exists so that I could use it.

[nathanchase]

For what it's worth, unflatten has been in sharp since April 2023.
lovell/sharp#1648 (comment)

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

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Run ID: 917e96fb-1c5a-4409-b0ac-c084b2e96cf0

📥 Commits

Reviewing files that changed from the base of the PR and between a371c17 and 1ba36ef.

📒 Files selected for processing (1)

• src/ipx.ts

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📝 Walkthrough

Walkthrough

Adds unflatten to the public modifier interface and exports a handler that invokes pipe.unflatten(). The README Modifiers table formatting is adjusted around the blur and unflatten rows.

Changes

Unflatten modifier

Layer / File(s)	Summary
Export and document unflatten src/ipx.ts, src/handlers/handlers.ts, README.md	The modifier interface accepts unflatten, the handler calls pipe.unflatten() without arguments, and the Modifiers table formatting is updated around the new entry.

Estimated code review effort: 1 (Trivial) | ~3 minutes

Suggested reviewers: pi0

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: adding an unflatten handler.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[pi0]

Seems not experimental anymore! Thanks!

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@README.md`:
- Around line 168-169: Update the blur and unflatten rows in the operation
table: add blur’s missing fourth cell and trailing table delimiter, and mark
unflatten as experimental while preserving its existing documentation link and
example path.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

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Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 2a2b3351-5d2e-4ca4-a8df-cab5488f822d

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Reviewing files that changed from the base of the PR and between aa94ce2 and e3fb037.

📒 Files selected for processing (2)

• README.md
• src/handlers/handlers.ts

[coderabbitai]

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

README.md (1)

192-193: 🎯 Functional Correctness | 🟡 Minor | ⚡ Quick win

Add the missing comments cells to these table rows.

Lines 192-193 contain only three cells instead of the four declared by the header, so the Markdown table is malformed and may render with shifted columns. Add an empty fourth cell and trailing delimiter to both rows.

Proposed fix

-| width / w      | [Docs](https://sharp.pixelplumbing.com/api-resize#resize)       | `/width_200/buffalo.png` or `/w_200/buffalo.png`     |
-| height / h     | [Docs](https://sharp.pixelplumbing.com/api-resize#resize)       | `/height_200/buffalo.png` or `/h_200/buffalo.png`    |
+| width / w      | [Docs](https://sharp.pixelplumbing.com/api-resize#resize)       | `/width_200/buffalo.png` or `/w_200/buffalo.png`     | |
+| height / h     | [Docs](https://sharp.pixelplumbing.com/api-resize#resize)       | `/height_200/buffalo.png` or `/h_200/buffalo.png`    | |

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@README.md` around lines 192 - 193, Add the missing empty comments cell and
trailing table delimiter to both the width / w and height / h rows in the
Markdown table, preserving their existing parameter, documentation, and example
cells.

Source: Linters/SAST tools

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Outside diff comments:
In `@README.md`:
- Around line 192-193: Add the missing empty comments cell and trailing table
delimiter to both the width / w and height / h rows in the Markdown table,
preserving their existing parameter, documentation, and example cells.

---

ℹ️ Review info

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Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: abe4c1d3-8f95-46c5-99b2-a1213ecf7d4a

📥 Commits

Reviewing files that changed from the base of the PR and between e3fb037 and a371c17.

📒 Files selected for processing (2)

• README.md
• src/handlers/handlers.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• src/handlers/handlers.ts