Debugging and preflight

Preflight is a gate, not a suggestion. A file is not production-ready until source validation, runtime validation, visual checks, and public page checks all agree.

Recommended preflight order

• Validate JSON against the generated schema.
• Load the file in a production-equivalent page.
• Run await FasterMotion.debug.validate() and treat error-severity results as blockers.
• Inspect the relevant surface: selectors for DOM, scene wires/textures for 3D, physics readers for physics, state-machine readers for interaction.
• Capture desktop and mobile screenshots or video proof.

Common failure classes

• Missing or invalid selectors.
• Dead node or port wires.
• Two writers owning the same transform component.
• Scroll trigger runway that cannot reach the intended progress.
• Malformed responsive gates or overrides.
• Blank Canvas or 3D frames caused by missing mounts, assets, or offscreen generated resources.

What to record

• The .fmtion source path and version.
• The page URL and viewport.
• Validation output and accepted warnings.
• Screenshots or video frames for the visual surface.
• The exact node, selector, scene, or asset ID involved in a failure.

Verified runnable examples

This guide points to proof-backed sample coverage. The full ledger lives in Generated examples and proof log.

DOM: Scroll fade reveal

• Source: faster-motion/demo/tests/dom/catalog/scroll-animations/fade-reveal/fade-reveal.domgraph.fmtion
• Expected output: Sections fade and translate into place as their trigger elements enter the configured viewport range.
• Validation: Schema validation passed. Runtime proof reports zero structural/runtime issues and 17 loaded nodes.
• Desktop proof: generated-assets/faster-motion-docs/proofs/screenshots/dom-fade-reveal-desktop.png
• Mobile proof: generated-assets/faster-motion-docs/proofs/screenshots/dom-fade-reveal-mobile.png

Canvas: Fill rule diagnostic

• Source: faster-motion/demo/tests/canvas/fillrule-diagnostic/fillrule-diagnostic.fmtion
• Expected output: A contained Canvas scene renders paired path cases so nonzero and evenodd fill handling can be compared visually.
• Validation: Schema validation passed. Runtime proof reports zero blocking runtime issues and 10 rendered objects; the accepted metadata note is preserved in the proof ledger.
• Desktop proof: generated-assets/faster-motion-docs/proofs/screenshots/canvas-fillrule-diagnostic-desktop.png
• Mobile proof: generated-assets/faster-motion-docs/proofs/screenshots/canvas-fillrule-diagnostic-mobile.png

Guide-specific sample target: Debug sample with one intentionally broken selector, validation output, fix, and clean validation output.

Faster Motion docs

Use this local map together with the left navigation. The source-backed content tree controls the main article order; this section keeps related pages one click away.

Start

• Faster Motion docs map
• Faster Motion documentation overview
• Get started with Faster Motion
• Faster Motion concepts
• .fmtion file format

DOM animation

• DOM animation guide
• DOM selectors and targets
• Scroll animation
• Pointer, hover, and drag inputs
• Text, SVG, and path animation
• Responsive gates and parameter overrides

Canvas animation

• Canvas animation guide
• Canvas area lifecycle
• Canvas objects, assets, and rendering
• Canvas inputs and state machines

3D and procedural

• Canvas 3D and procedural guide
• 3D scenes, cameras, and lights
• Procedural geometry and fields
• Particles and physics

Reference

• Node reference index
• Node categories reference
• Runtime loading and publishing
• Runtime API reference
• Debugging and preflight
• Debug API reference
• Validation errors and warning codes
• Faster Motion production checklist
• Faster Motion recipes overview