[nev21]

Bug fixes

• arrUnique / arrUnion: objects, arrays, functions and dates are now compared by identity (as documented) rather than by their string form, which discarded distinct values (arrUnique([{ a: 1 }, { b: 2 }]) returned [{ a: 1 }]); a Symbol no longer throws. Uses a new internal identity map (native Map when available, otherwise an array-based fallback)
• encodeAsBase64 / decodeBase64 (and the URL variants) now use the native btoa / atob in browsers; they were called with the wrong this so every call threw and fell back to the polyfill, which differed from Node (decodeBase64("QQ") returned "A\0\0", wrapped values were corrupted)
• encodeAsHex / encodeAsBase64 / encodeAsBase64Url no longer corrupt text containing characters above U+00FF
  • Output change: only for text that was previously corrupted, this is now encoded as the UTF-8 BOM followed by the UTF-8 bytes, eg. encodeAsHex("€") -> "efbbbfe282ac" (was "ac"); all other text is unchanged. The decode functions treat a value as UTF-8 only when it starts with the BOM and is valid UTF-8
• objCopyProps / objExtend: the prototype pollution guard now checks the target (it checked the source), so built-in prototypes can't be changed; docs now state that only own enumerable properties are copied and that proto / constructor / prototype are skipped
• objDeepCopy: handlers receive the correct path for an empty string key and for a key of 0 passed to details.copy()
• arrForEach no longer throws for a string (the "in" check uses the String wrapper, created once per call and only for strings), which also fixes arrChunk, arrCompact, arrUnique, arrGroupBy, arrPartition, arrDropWhile, arrTakeWhile, arrIntersection, arrDifference and arrFlatten; arrShuffle and polyArrWith also support a string
• polyArrAt / polyArrWith / polyArrFill convert their indexes like the native functions (+x || 0, range check, then |0), so fractional, NaN, undefined and numeric string indexes no longer return undefined, fill nothing, or add fractional properties to the array; polyArrWith([], -0.5) now throws like native. polyStrAt relies on polyArrAt for this
• polyArrFindLastIndex / polyArrFindLast now visit every index like the native functions (and as documented); empty slots of a sparse array were skipped and a string threw a TypeError
• iterTake closes the source iterator on the next() after the last value (like Iterator.prototype.take), not before the last value is consumed
• arrIntersection / arrUnion no longer throw for a null or undefined array after the first (treated as empty / ignored)
• scheduleMicrotask / scheduleNextTick no longer report enabled for a task a custom scheduleFn rejected or ran synchronously

Performance

• objCopyProps, objExtend, deepExtend and objDeepCopy skip creating a copy context for primitive values when there is no handler (~80% faster for objects of primitives)
• objDeepCopy / objCopyProps track visited objects with a Map when available, removing the quadratic slow down (16,000 objects: ~585ms -> ~48ms)
• encodeAsBase64 / decodeBase64 are ~10x faster in browsers now that the native functions no longer throw on every call
• polyArrFill no longer calls mathMin / mathMax (~17% faster)

Tests and size

• New tests for unique, the identity map (with and without Map), string input to the array helpers, and comparisons against the native at / with / fill across ~45 kinds of index value, plus additions for encode, copy, union, intersection, iterTake, microtasks and findLastIndex
• Size limits raised slightly for the encoding and identity map additions (es5-full 40.14 kB of 40.5 kB)

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[codecov]

Codecov Report

❌ Patch coverage is 99.45946% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 99.23%. Comparing base (f3a3c14) to head (3a6ef03).

Files with missing lines	Patch %	Lines
lib/src/helpers/encode.ts	98.18%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #642   +/-   ##
=======================================
  Coverage   99.22%   99.23%           
=======================================
  Files         181      182    +1     
  Lines        5688     5726   +38     
  Branches     1323     1340   +17     
=======================================
+ Hits         5644     5682   +38     
  Misses         44       44           

Files with missing lines	Coverage Δ
lib/src/array/at.ts	100.00% <100.00%> (ø)
lib/src/array/drop.ts	100.00% <100.00%> (ø)
lib/src/array/drop_while.ts	100.00% <100.00%> (ø)
lib/src/array/fill.ts	100.00% <100.00%> (ø)
lib/src/array/forEach.ts	100.00% <100.00%> (ø)
lib/src/array/intersection.ts	100.00% <100.00%> (ø)
lib/src/array/rotate.ts	100.00% <100.00%> (ø)
lib/src/array/shuffle.ts	100.00% <100.00%> (ø)
lib/src/array/slice.ts	100.00% <100.00%> (ø)
lib/src/array/take.ts	100.00% <100.00%> (ø)
... and 11 more

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[Copilot]

🟡 Changes recommended

Several active moderate issues remain in array index handling and string support, including 32-bit wraparound that targets incorrect positions and a string path that returns the wrong result type.

4 open issues

• Avoid 32-bit index wraparound in array access · New
• Avoid 32-bit index wraparound when filling ranges · New
• Return an array when dropping from string input · New
• Preserve large indexes in array replacement · New

_{Review effort: Lite}

[nevware21-bot]

Approved by nevware21-bot

[Copilot]

🔵 Needs a closer look

A moderate active finding remains in lib/src/array/rotate.ts: non-zero string rotations can produce whole string segments instead of individual characters on ES5 runtimes.

1 open issue

• Return an array when dropping from string input

1 previously missed issue

In code that hasn't changed since last review

Convert rotation slices to arrays for strings

lib/​src/​array/​rotate.ts:9

The non-zero rotation branch still uses arrSlice for the two pieces below. For a string, arrSlice resolves String.prototype.slice and returns strings; on ES5 runtimes where strings are not iterable, arrAppend adds each piece as one element, so arrRotate("abc", 1) becomes ["bc", "a"] instead of ['b', 'c', 'a']. Use _arrSliceToArr for all slices (for example, alias it as arrSlice in this import).

3 resolved since last review

• Preserve large indexes in array replacement
• Avoid 32-bit index wraparound when filling ranges
• Avoid 32-bit index wraparound in array access

_{Review effort: Lite}

[nevware21-bot]

Approved by nevware21-bot