Fix `thisArg` binding in `polyArrFindIndex` / `polyArrFindLastIndex` polyfills by Copilot · Pull Request #562 · nevware21/ts-utils

Copilot · 2026-05-15T20:35:33Z

polyArrFindIndex and polyArrFindLastIndex were using bitwise OR (|) when resolving callback context, which coerced object thisArg values and broke callback this binding. This updates both polyfills to use logical fallback semantics as intended.

Polyfill callback context fix
- Replaced thisArg | theArray with thisArg || theArray in:
  - lib/src/polyfills/array.ts (polyArrFindIndex)
  - lib/src/polyfills/array.ts (polyArrFindLastIndex)
- Effect: callback this now correctly uses the provided thisArg, and falls back to theArray only when thisArg is not provided/falsy.
Regression coverage
- Added focused tests in lib/test/src/common/polyfills/array.test.ts for both functions to verify:
  - explicit thisArg is preserved as callback this
  - default fallback binds callback this to the source array

// before (buggy)
callbackFn[CALL](thisArg | theArray as any, value, index, theArray);

// after
callbackFn[CALL](thisArg || theArray as any, value, index, theArray);

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

accounts.google.com
- Triggering command: /proc/self/exe /proc/self/exe --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=network --no-sandbox --disable-dev-shm-usage --use-angle=swiftshader-webgl --crashpad-handler-pid=4244 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/karma-7608247 --change-stack-guard-on-fork=enable --shared-files=network_parent_dirs_pipe:100,v8_context_snapshot_data:101 --field-trial-handle=3,i,17861204591039112903,10939758914733537520,262144 --disable-features=PaintHolding --variations-seed-version --pseudonymization-salt-handle=7,i,16105935546789010716,16606217994416365594,4 --trace-process-track-uuid=3190708989122997041 (dns block)
- Triggering command: /home/REDACTED/.cache/puppeteer/chrome/linux-148.0.7778.97/chrome-linux64/chrome /home/REDACTED/.cache/puppeteer/chrome/linux-148.0.7778.97/chrome-linux64/chrome --user-data-dir=/tmp/karma-7608247 --enable-automation --no-default-browser-check --no-first-run --disable-default-apps --disable-popup-blocking --disable-translate --disable-REDACTED-timer-throttling --disable-renderer-REDACTEDing --disable-device-discovery-notifications --no-sandbox --disable-gpu --disable-web-security --disable-dev-shm-usage http://localhost:9876/?id=7608247 --headless --disable-gpu --disable-dev-shm-usage --remote-debugging-port=9222 (dns block)
- Triggering command: /proc/self/exe /proc/self/exe --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=network --no-sandbox --disable-dev-shm-usage --use-angle=swiftshader-webgl --crashpad-handler-pid=4481 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/karma-68332849 --change-stack-guard-on-fork=enable --shared-files=network_parent_dirs_pipe:100,v8_context_snapshot_data:101 --field-trial-handle=3,i,7502828240700176064,4166064653183156238,262144 --disable-features=PaintHolding --variations-seed-version --pseudonymization-salt-handle=7,i,16762107709327361543,16977408465753334385,4 --trace-process-track-uuid=3190708989122997041 (dns block)
clients2.google.com
- Triggering command: /proc/self/exe /proc/self/exe --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=network --no-sandbox --disable-dev-shm-usage --use-angle=swiftshader-webgl --crashpad-handler-pid=4244 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/karma-7608247 --change-stack-guard-on-fork=enable --shared-files=network_parent_dirs_pipe:100,v8_context_snapshot_data:101 --field-trial-handle=3,i,17861204591039112903,10939758914733537520,262144 --disable-features=PaintHolding --variations-seed-version --pseudonymization-salt-handle=7,i,16105935546789010716,16606217994416365594,4 --trace-process-track-uuid=3190708989122997041 (dns block)
- Triggering command: /home/REDACTED/.cache/puppeteer/chrome/linux-148.0.7778.97/chrome-linux64/chrome /home/REDACTED/.cache/puppeteer/chrome/linux-148.0.7778.97/chrome-linux64/chrome --user-data-dir=/tmp/karma-7608247 --enable-automation --no-default-browser-check --no-first-run --disable-default-apps --disable-popup-blocking --disable-translate --disable-REDACTED-timer-throttling --disable-renderer-REDACTEDing --disable-device-discovery-notifications --no-sandbox --disable-gpu --disable-web-security --disable-dev-shm-usage http://localhost:9876/?id=7608247 --headless --disable-gpu --disable-dev-shm-usage --remote-debugging-port=9222 (dns block)
- Triggering command: /proc/self/exe /proc/self/exe --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=network --no-sandbox --disable-dev-shm-usage --use-angle=swiftshader-webgl --crashpad-handler-pid=4481 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/karma-68332849 --change-stack-guard-on-fork=enable --shared-files=network_parent_dirs_pipe:100,v8_context_snapshot_data:101 --field-trial-handle=3,i,7502828240700176064,4166064653183156238,262144 --disable-features=PaintHolding --variations-seed-version --pseudonymization-salt-handle=7,i,16762107709327361543,16977408465753334385,4 --trace-process-track-uuid=3190708989122997041 (dns block)
redirector.gvt1.com
- Triggering command: /proc/self/exe /proc/self/exe --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=network --no-sandbox --disable-dev-shm-usage --use-angle=swiftshader-webgl --crashpad-handler-pid=4244 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/karma-7608247 --change-stack-guard-on-fork=enable --shared-files=network_parent_dirs_pipe:100,v8_context_snapshot_data:101 --field-trial-handle=3,i,17861204591039112903,10939758914733537520,262144 --disable-features=PaintHolding --variations-seed-version --pseudonymization-salt-handle=7,i,16105935546789010716,16606217994416365594,4 --trace-process-track-uuid=3190708989122997041 (dns block)
- Triggering command: /home/REDACTED/.cache/puppeteer/chrome/linux-148.0.7778.97/chrome-linux64/chrome /home/REDACTED/.cache/puppeteer/chrome/linux-148.0.7778.97/chrome-linux64/chrome --user-data-dir=/tmp/karma-7608247 --enable-automation --no-default-browser-check --no-first-run --disable-default-apps --disable-popup-blocking --disable-translate --disable-REDACTED-timer-throttling --disable-renderer-REDACTEDing --disable-device-discovery-notifications --no-sandbox --disable-gpu --disable-web-security --disable-dev-shm-usage http://localhost:9876/?id=7608247 --headless --disable-gpu --disable-dev-shm-usage --remote-debugging-port=9222 (dns block)
- Triggering command: /proc/self/exe /proc/self/exe --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=network --no-sandbox --disable-dev-shm-usage --use-angle=swiftshader-webgl --crashpad-handler-pid=4481 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/karma-68332849 --change-stack-guard-on-fork=enable --shared-files=network_parent_dirs_pipe:100,v8_context_snapshot_data:101 --field-trial-handle=3,i,7502828240700176064,4166064653183156238,262144 --disable-features=PaintHolding --variations-seed-version --pseudonymization-salt-handle=7,i,16762107709327361543,16977408465753334385,4 --trace-process-track-uuid=3190708989122997041 (dns block)
www.google.com
- Triggering command: /proc/self/exe /proc/self/exe --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=network --no-sandbox --disable-dev-shm-usage --use-angle=swiftshader-webgl --crashpad-handler-pid=4244 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/karma-7608247 --change-stack-guard-on-fork=enable --shared-files=network_parent_dirs_pipe:100,v8_context_snapshot_data:101 --field-trial-handle=3,i,17861204591039112903,10939758914733537520,262144 --disable-features=PaintHolding --variations-seed-version --pseudonymization-salt-handle=7,i,16105935546789010716,16606217994416365594,4 --trace-process-track-uuid=3190708989122997041 (dns block)
- Triggering command: /home/REDACTED/.cache/puppeteer/chrome/linux-148.0.7778.97/chrome-linux64/chrome /home/REDACTED/.cache/puppeteer/chrome/linux-148.0.7778.97/chrome-linux64/chrome --user-data-dir=/tmp/karma-7608247 --enable-automation --no-default-browser-check --no-first-run --disable-default-apps --disable-popup-blocking --disable-translate --disable-REDACTED-timer-throttling --disable-renderer-REDACTEDing --disable-device-discovery-notifications --no-sandbox --disable-gpu --disable-web-security --disable-dev-shm-usage http://localhost:9876/?id=7608247 --headless --disable-gpu --disable-dev-shm-usage --remote-debugging-port=9222 (dns block)
- Triggering command: /proc/self/exe /proc/self/exe --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=network --no-sandbox --disable-dev-shm-usage --use-angle=swiftshader-webgl --crashpad-handler-pid=4481 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/karma-68332849 --change-stack-guard-on-fork=enable --shared-files=network_parent_dirs_pipe:100,v8_context_snapshot_data:101 --field-trial-handle=3,i,7502828240700176064,4166064653183156238,262144 --disable-features=PaintHolding --variations-seed-version --pseudonymization-salt-handle=7,i,16762107709327361543,16977408465753334385,4 --trace-process-track-uuid=3190708989122997041 (dns block)
www.googleapis.com
- Triggering command: /usr/local/bin/node node install.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

Configure Actions setup steps to set up my environment, which run before the firewall is enabled
Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Copilot

Pull request overview

This PR fixes callback this binding in array find-index polyfills and adds regression coverage for the corrected behavior.

Changes:

Updates polyArrFindIndex and polyArrFindLastIndex callback invocation context handling.
Adds tests verifying object thisArg binding and default array binding.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
`lib/src/polyfills/array.ts`	Adjusts callback `thisArg` fallback logic for find-index polyfills.
`lib/test/src/common/polyfills/array.test.ts`	Adds regression tests for callback context binding.

Comments suppressed due to low confidence (1)

lib/src/polyfills/array.ts:275

Using || still replaces explicitly supplied falsy thisArg values such as 0, false, or "" with the source array, so callbacks cannot observe those valid bindings. Use a check that only falls back when no usable default was intended (for example omitted/nullish, per the API docs) and add a regression case for falsy thisArg values.

        if (idx in theArray && callbackFn[CALL](thisArg || theArray as any, theArray[idx], idx, theArray)) {

codecov · 2026-05-15T23:51:07Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.43%. Comparing base (26b4766) to head (745458e).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #562   +/-   ##
=======================================
  Coverage   99.43%   99.43%           
=======================================
  Files         150      150           
  Lines        4452     4452           
  Branches      956      955    -1     
=======================================
  Hits         4427     4427           
  Misses         25       25

Files with missing lines	Coverage Δ
lib/src/polyfills/array.ts	`100.00% <100.00%> (ø)`

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

Copilot

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

Agent-Logs-Url: https://github.com/nevware21/ts-utils/sessions/5e6a31e7-083e-47d8-973e-0f74f23dc2b0 Co-authored-by: MSNev <54870357+MSNev@users.noreply.github.com>

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Agent-Logs-Url: https://github.com/nevware21/ts-utils/sessions/5e6a31e7-083e-47d8-973e-0f74f23dc2b0 Co-authored-by: MSNev <54870357+MSNev@users.noreply.github.com>

Copilot

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

## Release v0.14.0 This PR increases the version to `0.14.0` and updates the changelog with all significant changes since v0.13.0. ### Summary of Changes #### Features - New array helpers and array-like detection (#525) - `strReplace` and `strReplaceAll` string helpers (#527) - `strCapitalizeWords` helper (#528) - `strTruncate`, `strCount`, `strAt`, `strMatchAll` helpers (#529, #530) - `arrFlatMap` with ES5 polyfill (#533) - Typing utilities and expanded TSDoc examples (#535) - `isAsyncIterable` and `isIntegerInRange` helpers (#536) - `strStartsWithAny`, `strEndsWithAny`, `strWrap`, `strUnwrap`, `strNormalizeNewlines` (#543) - New object utility helpers and prototype pollution hardening (#564, #565) #### Bug Fixes - Fix ES2015 built-in type errors in consumers by adding lib reference directive to published declarations (#558) - Fix `thisArg` binding in `polyArrFindIndex` / `polyArrFindLastIndex` polyfills (#562) - Fix falsy `thisArg` (0, `''`, `false`) being overridden in `arrForEach`, `iterForOf`, `objForEachKey` (#566) #### Repository Improvements - Drop Node.js 16 from CI matrix and add Node.js 24 (#549) - Upgrade Grunt devDependency to v1.6.2 (#552) - Add funding metadata to published package manifests (#554) ### Files Updated - `CHANGELOG.md` — Added v0.14.0 entry - `package.json` — Version bumped to 0.14.0 - `lib/package.json` — Version bumped to 0.14.0 - `README.md` — Updated recommended version specification

Copilot AI assigned Copilot and MSNev May 15, 2026

Copilot started work on behalf of MSNev May 15, 2026 20:35 View session

Copilot AI linked an issue May 15, 2026 that may be closed by this pull request

Bug: Bitwise OR (|) instead of logical OR (||) in polyArrFindIndex/polyArrFindLastIndex #560

Closed

Copilot AI changed the title ~~[WIP] Fix bug: Use logical OR in polyArrFindIndex and polyArrFindLastIndex~~ Fix thisArg binding in polyArrFindIndex / polyArrFindLastIndex polyfills May 15, 2026

Copilot finished work on behalf of MSNev May 15, 2026 20:43

Copilot AI requested a review from MSNev May 15, 2026 20:43

MSNev marked this pull request as ready for review May 15, 2026 23:48

MSNev requested a review from a team as a code owner May 15, 2026 23:48

Copilot AI review requested due to automatic review settings May 15, 2026 23:48

MSNev requested a review from a team as a code owner May 15, 2026 23:48

Copilot started reviewing on behalf of MSNev May 15, 2026 23:49 View session

Copilot AI reviewed May 15, 2026

View reviewed changes

Comment thread lib/src/polyfills/array.ts Outdated

MSNev requested a review from Copilot May 16, 2026 01:36

Copilot started reviewing on behalf of MSNev May 16, 2026 01:36 View session

Copilot AI reviewed May 16, 2026

View reviewed changes

Comment thread lib/src/polyfills/array.ts Outdated

Copilot AI and others added 4 commits May 17, 2026 10:08

Initial plan

12ea701

fix(polyfills): use logical thisArg fallback in find index polyfills

b07a7d2

Agent-Logs-Url: https://github.com/nevware21/ts-utils/sessions/5e6a31e7-083e-47d8-973e-0f74f23dc2b0 Co-authored-by: MSNev <54870357+MSNev@users.noreply.github.com>

Apply suggestions from code review

3122927

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

fix(polyfills): use logical thisArg fallback in find index polyfills

745458e

Agent-Logs-Url: https://github.com/nevware21/ts-utils/sessions/5e6a31e7-083e-47d8-973e-0f74f23dc2b0 Co-authored-by: MSNev <54870357+MSNev@users.noreply.github.com>

nev21 force-pushed the copilot/fix-bitwise-or-in-polyfills branch from 3879d25 to 745458e Compare May 17, 2026 17:09

nev21 requested a review from Copilot May 17, 2026 17:31

Copilot started reviewing on behalf of nev21 May 17, 2026 17:32 View session

Copilot AI reviewed May 17, 2026

View reviewed changes

nev21 enabled auto-merge (squash) May 17, 2026 17:39

nev21 approved these changes May 17, 2026

View reviewed changes

nev21 merged commit d65f853 into main May 17, 2026
13 of 14 checks passed

nev21 deleted the copilot/fix-bitwise-or-in-polyfills branch May 17, 2026 17:39

nev21 mentioned this pull request May 19, 2026

[Release] Increase version to 0.14.0 #567

Merged

nev21 added this to the 0.14.0 milestone May 19, 2026

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Fix `thisArg` binding in `polyArrFindIndex` / `polyArrFindLastIndex` polyfills#562

Fix `thisArg` binding in `polyArrFindIndex` / `polyArrFindLastIndex` polyfills#562
nev21 merged 4 commits into
mainfrom
copilot/fix-bitwise-or-in-polyfills

Copilot AI commented May 15, 2026 •

edited

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

Uh oh!

codecov Bot commented May 15, 2026 •

edited

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

Uh oh!

Copilot AI left a comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Uh oh!

Conversation

Copilot AI commented May 15, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

I tried to connect to the following addresses, but was blocked by firewall rules:

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Uh oh!

codecov Bot commented May 15, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Codecov Report

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Copilot AI commented May 15, 2026 •

edited

Loading

codecov Bot commented May 15, 2026 •

edited

Loading