AbortSignal/AbortController doesn't work

Description

• AbortController / AbortSignal are used in javascript to cancel a request started with fetch, or any other async task that should be cancellable (docs here)
• In react native, there are several issues with these APIs:
  • DOMException, which is thrown when AbortController is used, doesn't actually exist as a type
  • Calling abortController.abort() doesn't actually have any effect, and abortSignal.reason is undefined.
  • abortSignal.throwIfAborted() doesn't exist as a function
  • I haven't fully verified this, but it looks like AbortController doesn't actually fully abort fetch requests.

Steps to reproduce

• Use javascript AbortController the way it's documented here

React Native Version

0.76.1

Affected Platforms

Runtime - Android, Runtime - iOS

Output of npx @react-native-community/cli info

System:
  OS: macOS 15.3.1
  CPU: (14) arm64 Apple M4 Max
  Memory: 175.34 MB / 36.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 22.14.0
    path: ~/.nvm/versions/node/v22.14.0/bin/node
  Yarn:
    version: 1.22.22
    path: ~/.nvm/versions/node/v22.14.0/bin/yarn
  npm:
    version: 10.9.2
    path: ~/.nvm/versions/node/v22.14.0/bin/npm
  Watchman: Not Found
Managers:
  CocoaPods:
    version: 1.16.2
    path: /Users/luisfinke/.rvm/gems/ruby-3.2.0/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 24.2
      - iOS 18.2
      - macOS 15.2
      - tvOS 18.2
      - visionOS 2.2
      - watchOS 11.2
  Android SDK: Not Found
IDEs:
  Android Studio: 2024.2 AI-242.23726.103.2422.13103373
  Xcode:
    version: 16.2/16C5032a
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 23.0.1
    path: /usr/bin/javac
  Ruby:
    version: 3.2.0
    path: /Users/luisfinke/.rvm/rubies/ruby-3.2.0/bin/ruby
npmPackages:
  "@react-native-community/cli": Not Found
  react:
    installed: 18.3.1
    wanted: 18.3.1
  react-native:
    installed: 0.76.1
    wanted: 0.76.1
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: Not found
  newArchEnabled: Not found
iOS:
  hermesEnabled: Not found
  newArchEnabled: Not found

Stacktrace or Logs

N/A

Reproducer

N/A

Screenshots and Videos

No response

Start with the documented AbortController and AbortSignal usage on React Native 0.76.1 for Android and iOS, checking abort(), reason, throwIfAborted(), and fetch cancellation. Compare the observed behavior with the expected web API behavior; the work is done when these reported API behaviors are correctly supported or their remaining limitations are clearly covered by tests.