Fix thisArg binding in polyArrFindIndex / polyArrFindLastIndex polyfills (#562)

`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

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

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

> [!WARNING]
>
> <details>
> <summary>Firewall rules blocked me from connecting to one or more
addresses (expand for details)</summary>
>
> #### 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
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---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
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Author: 4 people

lib/src/polyfills/array.ts

@@ -11,7 +11,7 @@ import { arrForEach } from "../array/forEach";
 import { arrIndexOf } from "../array/indexOf";
 import { arrMap } from "../array/map";
 import { arrSlice } from "../array/slice";
-import { isArray, isNullOrUndefined, objToString } from "../helpers/base";
+import { isArray, isNullOrUndefined, isStrictNullOrUndefined, objToString } from "../helpers/base";
 import { CALL, LENGTH } from "../internal/constants";
 import { iterForOf } from "../iterator/forOf";
 
@@ -158,7 +158,7 @@ export function polyArrFind<T, E extends T>(theArray: ArrayLike<T>, callbackFn:
 export function polyArrFindIndex<T, E extends T>(theArray: ArrayLike<T>, callbackFn: ArrPredicateCallbackFn<T, E> | ArrPredicateCallbackFn2<T>, thisArg?: any): number {
     let result = -1;
     arrForEach(theArray, (value, index) => {
-        if (callbackFn[CALL](thisArg | theArray as any, value, index, theArray)) {
+        if (callbackFn[CALL](isStrictNullOrUndefined(thisArg) ? theArray as any : thisArg, value, index, theArray)) {
             result = index;
             return -1;
         }
@@ -272,7 +272,7 @@ export function polyArrFindLastIndex<T, E extends T>(theArray: ArrayLike<T>, cal
     let result = -1;
     let len = theArray[LENGTH] >>> 0;
     for (let idx = len - 1; idx >= 0; idx--) {
-        if (idx in theArray && callbackFn[CALL](thisArg | theArray as any, theArray[idx], idx, theArray)) {
+        if (idx in theArray && callbackFn[CALL](isStrictNullOrUndefined(thisArg) ? theArray as any : thisArg, theArray[idx], idx, theArray)) {
             result = idx;
             break;
         }

lib/test/src/common/polyfills/array.test.ts

@@ -143,6 +143,67 @@ describe("array polyfills", () => {
             assert.equal(polyArrFindIndex([4, 6, 7, 9, 12], isPrime), 2);
             assert.equal(called, 3);
         });
+
+        it("supports callback thisArg and defaults to the array", () => {
+            const values = [1, 2, 3];
+            const thisArg = { match: 2 };
+            let cbThis: any = null;
+
+            assert.equal(polyArrFindIndex(values, function(value) {
+                cbThis = this;
+                return value === this.match;
+            }, thisArg), 1);
+            assert.equal(cbThis, thisArg);
+
+            cbThis = null;
+            assert.equal(polyArrFindIndex(values, function(value) {
+                cbThis = this;
+                return value === 3;
+            }), 2);
+            assert.equal(cbThis, values);
+
+            cbThis = null;
+            assert.equal(polyArrFindIndex(values, function(value) {
+                cbThis = this;
+                return value === 3;
+            }, undefined), 2);
+            assert.equal(cbThis, values);
+
+            cbThis = null;
+            assert.equal(polyArrFindIndex(values, function(value) {
+                cbThis = this;
+                return value === 3;
+            }, 0), 2);
+            assert.equal(cbThis, 0);
+
+            cbThis = null;
+            assert.equal(polyArrFindIndex(values, function(value) {
+                cbThis = this;
+                return value === 3;
+            }, ""), 2);
+            assert.equal(cbThis, "");
+
+            cbThis = null;
+            assert.equal(polyArrFindIndex(values, function(value) {
+                cbThis = this;
+                return value === 3;
+            }, false), 2);
+            assert.equal(cbThis, false);
+
+            cbThis = null;
+            assert.equal(polyArrFindIndex(values, function(value) {
+                cbThis = this;
+                return value === 3;
+            }, "undefined"), 2);
+            assert.equal(cbThis, "undefined");
+
+            cbThis = null;
+            assert.equal(polyArrFindIndex(values, function(value) {
+                cbThis = this;
+                return value === 3;
+            }, "null"), 2);
+            assert.equal(cbThis, "null");
+        });
     });
 
     describe("polyArrFindLast", () => {
@@ -228,6 +289,68 @@ describe("array polyfills", () => {
             assert.equal(polyArrFindLastIndex([4, 6, 7, 9, 12], isPrime), 2);
             assert.equal(called, 3);
         });
+
+        it("supports callback thisArg and defaults to the array", () => {
+            const values = [1, 2, 3];
+            const thisArg = { match: 2 };
+            let cbThis: any = null;
+
+            assert.equal(polyArrFindLastIndex(values, function(value) {
+                cbThis = this;
+                return value === this.match;
+            }, thisArg), 1);
+            assert.equal(cbThis, thisArg);
+
+            cbThis = null;
+            assert.equal(polyArrFindLastIndex(values, function(value) {
+                cbThis = this;
+                return value === 1;
+            }), 0);
+            assert.equal(cbThis, values);
+
+
+            cbThis = null;
+            assert.equal(polyArrFindLastIndex(values, function(value) {
+                cbThis = this;
+                return value === 1;
+            }, undefined), 0);
+            assert.equal(cbThis, values);
+
+            cbThis = null;
+            assert.equal(polyArrFindLastIndex(values, function(value) {
+                cbThis = this;
+                return value === 1;
+            }, 0), 0);
+            assert.equal(cbThis, 0);
+
+            cbThis = null;
+            assert.equal(polyArrFindLastIndex(values, function(value) {
+                cbThis = this;
+                return value === 1;
+            }, ""), 0);
+            assert.equal(cbThis, "");
+
+            cbThis = null;
+            assert.equal(polyArrFindLastIndex(values, function(value) {
+                cbThis = this;
+                return value === 1;
+            }, false), 0);
+            assert.equal(cbThis, false);
+
+            cbThis = null;
+            assert.equal(polyArrFindLastIndex(values, function(value) {
+                cbThis = this;
+                return value === 1;
+            }, "undefined"), 0);
+            assert.equal(cbThis, "undefined");
+
+            cbThis = null;
+            assert.equal(polyArrFindLastIndex(values, function(value) {
+                cbThis = this;
+                return value === 1;
+            }, "null"), 0);
+            assert.equal(cbThis, "null");
+        });
     });
 
     describe("polyArrFrom", () => {