Fix make _.isNumber(NaN) return false and update tests #5982

Rishiyaduwanshi · 2025-04-20T08:42:42Z

📌 Fix: `_.isNumber(NaN)` now returns `false` as expected (Fixes #5981)

🐛 The Issue

In Lodash v4.17.21, the _.isNumber function incorrectly returns true for NaN. This is problematic in scenarios where consumers of the library want to distinguish valid numbers from NaN.

Reference: Issue #5981

✅ The Fix

The isNumber function has been updated to return false when the input is NaN. The logic now ensures that:

Primitive NaN values are filtered out.
Boxed NaN values (e.g., Object(NaN)) are also handled appropriately.

    function isNumber(value) {
      return (typeof value == 'number' && !Number.isNaN(value)) ||  
             (isObjectLike(value) && baseGetTag(value) == numberTag);
    }

🧪 Tests Updated

Updated test case: assert.strictEqual(_.isNumber(NaN), false);
Verified against full test suite using pnpm test.
All tests passing ✅

Rishiyaduwanshi · 2025-04-28T17:53:26Z

Hi! Just following up on this PR. Let me know if any changes are needed. Thanks!

Fix make _.isNumber(NaN) return false and update tests

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Fix make _.isNumber(NaN) return false and update tests #5982

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Fix make _.isNumber(NaN) return false and update tests #5982

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Fix make _.isNumber(NaN) return false and update tests #5982

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📌 Fix: _.isNumber(NaN) now returns false as expected (Fixes #5981)

🐛 The Issue

✅ The Fix

🧪 Tests Updated

📌 Fix: `_.isNumber(NaN)` now returns `false` as expected (Fixes #5981)