feat: add TypeScript definitions for utf16.js

[Copilot]

Add TypeScript types for utf16.js

• Understand the issue and explore the repository
• Create utf16.d.ts file with TypeScript type definitions
• Update package.json to include types for utf16.js export
• Run linter to verify no issues (existing issues unrelated to changes)
• Run tests to validate the changes (all 19 tests pass)
• Request code review and address feedback
• Run security checks (no alerts found)
• Use Uint16ArrayBuffer type for consistency
• Move Uint16ArrayBuffer to array.d.ts for better organization
• Remove unrelated .gitignore change
• Remove blank line for cleaner formatting
• Remove duplicate comment
• Sync documentation to README
• Fix JSDoc formatting to match UTF-8 pattern throughout
• Add documentation for non-even byte length validation

Summary

Successfully added complete TypeScript type definitions for utf16.js module following the same pattern as utf8.d.ts. The implementation includes:

• Four exported functions with proper overloads for different format parameters
• Type-safe handling of 'uint16', 'uint8-le', and 'uint8-be' formats
• Uint16ArrayBuffer type definition in array.d.ts (next to Uint8ArrayBuffer) to prevent SharedArrayBuffer acceptance
• Complete JSDoc documentation with consistent formatting matching the existing codebase style
• Documentation for byte length validation (throws on non-even byte length for uint8-le/uint8-be formats)
• Updated package.json exports to include the types field
• Updated README.md with detailed API documentation for UTF-16 functions matching the UTF-8 section format
• All tests passing and no security vulnerabilities detected

Original prompt

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This section details on the original issue you should resolve

<issue_title>Types: utf16.js</issue_title>
<issue_description></issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Types: utf16.js #24

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[ChALkeR]

@copilot Use type Uint16ArrayBuffer = ReturnType<typeof Uint16Array.from>; for consistency with Uint8ArrayBuffer

We don't test these on SharedArrayBuffer as input yet

[Copilot]

@copilot Use type Uint16ArrayBuffer = ReturnType<typeof Uint16Array.from>; for consistency with Uint8ArrayBuffer

We don't test these on SharedArrayBuffer as input yet

Updated to use Uint16ArrayBuffer type following the same pattern as Uint8ArrayBuffer (8639a02)

[ChALkeR]

@copilot

Suggested change

	// >= TypeScript 5.9 made Uint16Array templated with <> and defaulted to ArrayBufferLike
	// which would incorrectly accept SharedArrayBuffer instances.
	// < TypeScript 5.7 doesn't support templates for Uint16Array.
	// So this type is defined as a workaround to evaluate to Uint16Array<ArrayBuffer> on all versions of TypeScript.

[Copilot]

Removed blank line between type definitions (099ae6b)

[ChALkeR]

@copilot sync these docs into README.md

[Copilot]

Added detailed UTF-16 API documentation to README.md matching the UTF-8 section format (93ccc67)

[ChALkeR]

@copilot this misses a newline. Ensure this is synced with README

[Copilot]

Fixed JSDoc formatting to use backslash continuation matching UTF-8 pattern and README (7761ebe)

[ChALkeR]

@copilot and here

[Copilot]

Fixed module-level JSDoc formatting with backslash continuation (d149023)

[ChALkeR]

Suggested change

	Throws on non-even byte length.

@copilot here and in README, for utf16toStringLoose

[Copilot]

Added note about throwing on non-even byte length to both utf16toString and utf16toStringLoose in utf16.d.ts and README.md (8aef664)

[Copilot]

Pull request overview

This PR adds TypeScript type definitions for the utf16.js module, enabling type-safe usage of UTF-16 encoding/decoding functions. The implementation follows the same pattern as the existing utf8.d.ts file and includes comprehensive JSDoc documentation.

Changes:

• Added TypeScript definitions with proper function overloads for format parameter type safety
• Introduced Uint16ArrayBuffer type in array.d.ts for consistency with Uint8ArrayBuffer
• Updated package.json to expose types in the exports map and files array
• Enhanced README.md with detailed API documentation matching the UTF-8 section format

Reviewed changes

Copilot reviewed 2 out of 4 changed files in this pull request and generated no comments.

File	Description
utf16.d.ts	New TypeScript definitions file with type-safe function overloads for utf16fromString, utf16fromStringLoose, utf16toString, and utf16toStringLoose, including comprehensive JSDoc documentation
array.d.ts	Added Uint16ArrayBuffer type definition next to Uint8ArrayBuffer for type safety
package.json	Added utf16.d.ts to files array and types field to utf16.js exports configuration
README.md	Added detailed API documentation for UTF-16 functions with descriptions, behavior notes, and format parameters

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