fix(compat/isNaN): improve NaN checks for boxed values and non-numbers

[D-Sketon]

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Project	Deployment	Actions	Updated (UTC)
es-toolkit	Ready	Preview, Comment	Apr 18, 2026 9:27am

[Copilot]

Pull request overview

This PR updates the compat/predicate/isNaN helper to correctly detect NaN for boxed number values (e.g. new Number(NaN)) while still returning false for non-numeric inputs, aligning behavior more closely with lodash.

Changes:

• Update isNaN implementation to gate on isNumber and handle boxed numbers via numeric unboxing.
• Extend isNaN tests to cover boxed number inputs (new Number(0) and new Number(NaN)).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/compat/predicate/isNaN.ts	Changes isNaN logic to handle boxed numbers via unboxing after a numeric-type gate.
src/compat/predicate/isNaN.spec.ts	Adds test cases for boxed non-NaN and boxed NaN values.

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.97%. Comparing base (c8fec98) to head (04e2d60).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1646   +/-   ##
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  Coverage   99.97%   99.97%           
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  Files         497      497           
  Lines        4660     4660           
  Branches     1348     1349    +1     
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  Hits         4659     4659           
  Misses          1        1           

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