Dactyloidae/browser/internaluserscripts

Internal Userscripts (Polyfills Only)

This directory contains a minimal, built-in userscript loader used to ship polyfill user scripts with Dactyloidae (forked from Basilisk's implementation of such). This originally started as a fork of GreaseMonkey, however at this point very little of GreaseMonkey remains.

How it works

• The XPCOM component @internaluserscripts.mozdev.org/service;1 observes document creation and, when browser.internal-userscripts.enabled is true, injects bundled polyfill scripts into each page.
• Bundled scripts live in basilisk/internaluserscripts/bundled-scripts/ and are packaged into the app. They are loaded in the page principal and can override missing APIs.
• The only default pref is browser.internal-userscripts.enabled (default: true). Toggle to disable all injection.

Bundled polyfills

• elementfrompoint-finite-polyfill.user.js: wraps Document.elementFromPoint() and Document.elementsFromPoint() to return null/[] when coordinates are not finite, avoiding page-breaking TypeErrors from non-finite inputs. It exposes window.__internalUserscriptsElementFromPointFinitePolyfill = true for verification.
• getanimations-polyfill.user.js: minimal getAnimations() shim for Document, Element, and CSSPseudoElement that returns an empty array when native support is unavailable. It exposes window.__internalUserscriptsGetAnimationsPolyfill = true for verification.
• imagedecode-polyfill.user.js: best-effort HTMLImageElement.decode() shim that resolves on load and rejects on error. It exposes window.__internalUserscriptsImageDecodePolyfill = true for verification.
• intl-displaynames-polyfill.user.js: minimal Intl.DisplayNames shim that validates options and returns the input code when display data is unavailable. It exposes window.__internalUserscriptsIntlDisplayNamesPolyfill = true for verification.
• intl-listformat-polyfill.user.js: minimal Intl.ListFormat shim supporting format() and formatToParts() with simple fallback separators. It exposes window.__internalUserscriptsIntlListFormatPolyfill = true for verification.
• intl-relativetimeformat-formattoparts-polyfill.user.js: adds formatToParts() to native Intl.RelativeTimeFormat implementations that lack it. It exposes window.__internalUserscriptsIntlRelativeTimeFormatFormatToPartsPolyfill = true for verification.
• intl-segmenter-polyfill.user.js: minimal Intl.Segmenter shim supporting segment(), resolvedOptions(), and supportedLocalesOf() with best-effort grapheme/word/sentence segmentation. It exposes window.__internalUserscriptsIntlSegmenterPolyfill = true for verification.
• readablestream-pipethrough-polyfill.user.js: best-effort ReadableStream pipeThrough implementation backed by pipeTo or reader/writer pumping. It exposes window.__internalUserscriptsReadableStreamPipeThroughPolyfill = true for verification.
• readablestream-pipeto-polyfill.user.js: best-effort ReadableStream pipeTo implementation using reader/writer pumping. It exposes window.__internalUserscriptsReadableStreamPipeToPolyfill = true for verification.
• textencoderstream-polyfill.user.js: best-effort TextEncoderStream implementation backed by TransformStream. It exposes window.__internalUserscriptsTextEncoderStreamPolyfill = true for verification.
• textdecoderstream-polyfill.user.js: best-effort TextDecoderStream implementation backed by TransformStream. It exposes window.__internalUserscriptsTextDecoderStreamPolyfill = true for verification.
• transformstream-polyfill.user.js: minimal TransformStream polyfill backed by ReadableStream with a lightweight WritableStream shim. It exposes window.__internalUserscriptsTransformStreamPolyfill = true for verification.
• webauthn-microsoft-shim.user.js: Microsoft-domain WebAuthn capability shim that reports WebAuthn as unsupported by providing rejecting navigator.credentials.create/get stubs (when navigator.credentials is missing) and a PublicKeyCredential.isUserVerifyingPlatformAuthenticatorAvailable() fallback that resolves false. It exposes window.__internalUserscriptsWebAuthnMicrosoftShim = true for verification.

Adding new polyfills

1. Drop a *.user.js file into bundled-scripts/ with the appropriate header.
2. List it in moz.build under FINAL_TARGET_FILES['internal-userscripts'].
3. The loader will inject it automatically when enabled.