Two rounds of regex/tokenizer patches to sanitizeSvg found new bypasses in the same shape each time (unquoted href, style= url(), aliased xlink prefix; then presentation-attribute url(), unquoted '=' handling, SMIL animate/set href rewrite, self-closing-slash tag corruption, data:image/ navigation via <a>). Denylisting attribute names against a hand-rolled tokenizer was the wrong approach regardless of how careful the regex. Rewrote sanitizeSvg (packages/core/src/figma/sanitizeSvg.ts) as a real DOM walk (linkedom, already a dependency of core and cli) with an allowlist: known-safe elements and attributes only, everything else dropped by construction rather than pattern-matched as dangerous. href/xlink:href (any namespace prefix) kept only for a same-document fragment, or data:image/ off non-<a> elements. Any attribute value or <style> text containing url() kept only when every url() argument is a fragment; @import/expression(/javascript: dropped from style content. Serializing from a real DOM means output is always well-formed, so the self-closing-slash corruption class of bug is gone by construction. media-use's own copy (packages/cli/src/media-use/lib/svg-sanitize.mjs) can't import linkedom directly: its CI test lane runs bare `node --test` with no install step, so even an external dependency fails to resolve, not just a workspace import. It's now a generated file instead of a hand-copy: scripts/generate-media-use-svg-sanitize.mjs bundles the core source (esbuild, minified, zero remaining imports) and scripts/check-media-use-svg-sanitize-generated.test.mjs fails the build on drift. Verified the generated file runs with plain node in an empty directory with no node_modules on the path. Every payload from both independent-review reports is now a table-driven test in sanitizeSvg.test.ts (46 cases) and the same corpus in check-svg-sanitize-parity.test.mjs (39 cases) asserts core and the generated media-use copy agree and each independently rejects every non-local url(), javascript:, data: href on <a>, and on* handler. Mutation-proved against the real pre-fix blob, not a synthetic case. Sampled 56 real theSVG icons across all 7 collections to check the allowlist doesn't over-strip legitimate content: found and fixed three missing attributes (fx/fy, enable-background, a blanket data-* allowance) and one real behavioral bug - <style> elements were being dropped outright, silently unstyling any Illustrator-exported logo that colors paths via CSS classes. Fixed by keeping <style> on the allowlist and content-checking its text the same way as an inline style= attribute, with a regression test using that exact shape. Full suite after the fix: sanitizeSvg.test.ts 46/46, parity+drift tests 39/39, media-use suite 298/298, tsc/oxlint/oxfmt clean.
@hyperframes/core
Types, parsers, generators, compiler, linter, runtime, and frame adapters for the Hyperframes video framework.
Install
npm install @hyperframes/core
Most users don't need to install core directly — the CLI, producer, and studio packages depend on it internally.
What's inside
| Module | Description |
|---|---|
| Types | TimelineElement, CompositionSpec, Asset, canvas dimensions, defaults |
| Parsers | parseHtml — extract timeline elements from HTML; parseGsapScript — parse GSAP animations |
| Generators | generateHyperframesHtml — produce valid Hyperframes HTML from a composition spec |
| Compiler | compileTimingAttrs — resolve data-start / data-duration into absolute times |
| Linter | lintHyperframeHtml — validate Hyperframes HTML (missing attributes, overlapping tracks, etc.) |
| Runtime | IIFE script injected into the browser — manages seek, media playback, and the window.__hf protocol |
| Frame Adapters | Pluggable animation drivers (GSAP, Lottie, CSS, or custom) |
Generated composition trust
Composition generators require trusted authors for code-bearing inputs. styles and
generateHyperframesStyles preserve authored CSS, which can load external resources.
animations may contain __raw: values that are emitted as JavaScript;
includeScripts: true includes executable timeline code. serializeGsapAnimations
also accepts raw preamble, postamble, and a code-bearing timelineVar. Never fill
these inputs with untrusted data. Attribute encoding and closing-tag containment
are not a sandbox; render untrusted compositions in an appropriately isolated
execution environment and never serve them on a privileged origin.
Text content retains the supported inline-formatting sanitizer contract. The clip parser intentionally flattens inner formatting to text, so parse/generate is not a lossless replacement for editing the source HTML.
Frame Adapters
A frame adapter tells the engine how to seek your animation to a specific frame:
import { createGSAPFrameAdapter } from "@hyperframes/core";
const adapter = createGSAPFrameAdapter({
getTimeline: () => gsap.timeline(),
compositionId: "my-video",
});
Implement FrameAdapter for custom animation runtimes:
import type { FrameAdapter } from "@hyperframes/core";
const myAdapter: FrameAdapter = {
id: "my-adapter",
getDurationFrames: () => 300,
seekFrame: (frame) => {
/* seek your animation */
},
};
Parsing and generating HTML
import { parseHtml, generateHyperframesHtml } from "@hyperframes/core";
const { elements, metadata } = parseHtml(htmlString);
const html = generateHyperframesHtml(spec);
Linting
import { lintHyperframeHtml } from "@hyperframes/core/lint";
const result = lintHyperframeHtml(htmlString);
// result.findings: { severity, message, elementId }[]
Documentation
Full documentation: hyperframes.heygen.com/packages/core
Related packages
@hyperframes/engine— rendering engine that drives the browser@hyperframes/producer— full render pipeline (capture + encode)hyperframes— CLI