feat(array): add new array helpers and array-like detection by nev21 · Pull Request #525 · nevware21/ts-utils

nev21 · 2026-02-26T06:36:02Z

add arrUnique, arrCompact, arrFlatten, arrGroupBy, arrChunk with ArrayLike support
add isArrayLike helper and export in index
add tests for new array helpers and isArrayLike

- add arrUnique, arrCompact, arrFlatten, arrGroupBy, arrChunk with ArrayLike support - add isArrayLike helper and export in index - add tests for new array helpers and isArrayLike

Copilot

Pull request overview

This pull request adds five new array helper functions with ArrayLike support and introduces the isArrayLike type guard helper. The changes enhance the library's array manipulation capabilities with common utility functions like deduplication, compaction, flattening, grouping, and chunking, all following the established arr* naming convention and supporting both arrays and array-like objects.

Changes:

Added isArrayLike helper function to detect array-like objects (objects with numeric length property >= 0)
Added five new array utility functions: arrUnique, arrCompact, arrFlatten, arrGroupBy, and arrChunk
Updated bundle size limits to accommodate the new functionality (~1KB increase)
Removed redundant /*#__PURE__*/ markers from simple function assignments in unwrapFunction.ts
Updated version documentation in customError.ts

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
lib/src/helpers/base.ts	Adds `isArrayLike` type guard function with proper null/undefined/function checks and exports it
lib/src/array/unique.ts	New function to remove duplicate values from arrays using object-based tracking
lib/src/array/compact.ts	New function to filter out all falsy values from arrays
lib/src/array/flatten.ts	New function to flatten nested arrays to specified depth
lib/src/array/groupBy.ts	New function to group array elements by callback result
lib/src/array/chunk.ts	New function to split arrays into fixed-size chunks
lib/src/index.ts	Exports all new functions and types including `isArrayLike`
lib/test/src/common/helpers/base.test.ts	Comprehensive tests for `isArrayLike` covering various input types
lib/test/src/common/helpers/array.test.ts	Comprehensive tests for all five new array functions
lib/src/internal/unwrapFunction.ts	Removes redundant `/#__PURE__/` markers from simple assignments
lib/src/helpers/customError.ts	Updates version comment from v0.12.7 to v0.13.0 for `superArgsFn` parameter
.size-limit.json	Updates bundle size limits to reflect new functionality
lib/test/bundle-size-check.js	Updates bundle size limits for ES5 and ES6 builds
README.md	Updates documentation to include new array functions in the function list

Copilot · 2026-02-26T06:46:03Z

lib/src/array/unique.ts

+ * Licensed under the MIT license.
+ */
+
+import { isArrayLike, isUndefined } from "../helpers/base";


The isUndefined import is unused and should be removed to keep the code clean and reduce bundle size.

Suggested change

import { isArrayLike, isUndefined } from "../helpers/base";

import { isArrayLike } from "../helpers/base";

Copilot · 2026-02-26T06:46:04Z

lib/src/array/unique.ts

+        const seen: any = objCreate(null);
+
+        arrForEach(theArray, (item) => {
+            const key = normalizeJsName((typeof item) + "_" + item);


Using normalizeJsName for deduplication keys is problematic. The normalizeJsName function is designed to convert strings into valid JavaScript identifiers by replacing invalid characters with underscores, not for creating unique deduplication keys.

This implementation has potential issues:

It's unnecessary overhead - the function performs regex replacement meant for identifier normalization

It could theoretically cause key collisions if values contain characters that get normalized (e.g., spaces, dots, special chars)

The approach works for primitives but would silently fail for objects (all objects would map to "object_[object Object]")

A simpler and more reliable approach would be to use the value directly as the key with type prefix, since JavaScript object keys are already strings:

const key = (typeof item) + ":" + item;

This avoids the normalization overhead and is clearer in intent. Alternatively, for ES6+ environments, consider using a Set or Map for better performance and correctness.

Copilot · 2026-02-26T06:46:04Z

lib/src/array/groupBy.ts

+            const keyStr = asString(callbackFn.call(thisArg, item, idx, theArray));
+
+            if (!objHasOwn(result, keyStr)) {
+                result[keyStr] = [];
+            }
+
+            result[keyStr].push(item);


The callback return value is being converted to string using asString, but the function signature indicates it can return string | number | symbol. Converting symbols to strings defeats their purpose as unique identifiers and may cause unexpected behavior. Numbers are fine to convert to strings for object keys, but symbols should be handled differently.

Consider checking the type and handling symbols separately, or document that symbols will be converted to strings (which would make them lose their uniqueness property). The return type and implementation should be consistent.

Suggested change

const keyStr = asString(callbackFn.call(thisArg, item, idx, theArray));

if (!objHasOwn(result, keyStr)) {

result[keyStr] = [];

}

result[keyStr].push(item);

const rawKey = callbackFn.call(thisArg, item, idx, theArray);

const key: string | number | symbol = typeof rawKey === "symbol" ? rawKey : asString(rawKey);

if (!objHasOwn(result, key)) {

result[key] = [];

}

result[key].push(item);

Copilot · 2026-02-26T06:46:04Z

lib/src/array/chunk.ts

+        let chunkIdx = 0;
+
+        arrForEach(theArray, (item) => {
+            if (idx % size === 0) {
+                result.push([]);
+                chunkIdx = result.length - 1;


The variable chunkIdx is recalculated as result.length - 1 on every chunk creation, but it could be simplified. Since chunks are added sequentially, you could just increment chunkIdx or track it more efficiently. However, the current implementation is clear and the performance impact is negligible, so this is a very minor optimization opportunity rather than a bug.

Suggested change

let chunkIdx = 0;

arrForEach(theArray, (item) => {

if (idx % size === 0) {

result.push([]);

chunkIdx = result.length - 1;

let chunkIdx = -1;

arrForEach(theArray, (item) => {

if (idx % size === 0) {

result.push([]);

chunkIdx++;

Copilot · 2026-02-26T06:46:04Z

lib/src/helpers/customError.ts

 * new Custom Error instance is being created.
 * @param errorBase - [Optional] (since v0.9.6) The error class to extend for this class, defaults to Error.
- * @param superArgsFn - [Optional] (since v0.12.7) An optional function that receives the constructor arguments and
+ * @param superArgsFn - [Optional] (since v0.13.0) An optional function that receives the constructor arguments and


The version number in the JSDoc comment for the superArgsFn parameter has been changed from v0.12.7 to v0.13.0. This change should be verified:

If the parameter was actually added in v0.12.7, this change is incorrect and breaks the documentation history

If the parameter is being added in this PR (v0.13.0), the change is correct

If the parameter existed but is being significantly modified in v0.13.0, that should be noted differently in the documentation

Please verify the git history to confirm whether this parameter existed in v0.12.7 or is being introduced in v0.13.0.

Suggested change

* @param superArgsFn - [Optional] (since v0.13.0) An optional function that receives the constructor arguments and

* @param superArgsFn - [Optional] (since v0.12.7) An optional function that receives the constructor arguments and

feat(array): add new array helpers and array-like detection

583d1cc

- add arrUnique, arrCompact, arrFlatten, arrGroupBy, arrChunk with ArrayLike support - add isArrayLike helper and export in index - add tests for new array helpers and isArrayLike

nev21 added this to the 0.13.0 milestone Feb 26, 2026

nev21 requested a review from a team as a code owner February 26, 2026 06:36

Copilot AI review requested due to automatic review settings February 26, 2026 06:36

nev21 requested a review from a team as a code owner February 26, 2026 06:36

Copilot started reviewing on behalf of nev21 February 26, 2026 06:36 View session

Copilot AI reviewed Feb 26, 2026

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nev21 modified the milestones: 0.13.0, 0.14.0 Mar 4, 2026

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feat(array): add new array helpers and array-like detection#525

feat(array): add new array helpers and array-like detection#525
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	import { isArrayLike, isUndefined } from "../helpers/base";
	import { isArrayLike } from "../helpers/base";

-            const keyStr = asString(callbackFn.call(thisArg, item, idx, theArray));
-            if (!objHasOwn(result, keyStr)) {
-                result[keyStr] = [];
-            }
-            result[keyStr].push(item);
+            const rawKey = callbackFn.call(thisArg, item, idx, theArray);
+            const key: string | number | symbol = typeof rawKey === "symbol" ? rawKey : asString(rawKey);
+            if (!objHasOwn(result, key)) {
+                result[key] = [];
+            }
+            result[key].push(item);

	* @param superArgsFn - [Optional] (since v0.13.0) An optional function that receives the constructor arguments and
	* @param superArgsFn - [Optional] (since v0.12.7) An optional function that receives the constructor arguments and

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Pull request overview

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