Function resolveConversionProps

packages/parsers/src/gsapSerialize.ts:483–512

(
  anim: GsapAnimation,
  resolvedFromValues?: Record<string, number | string>,
)

 *   - For fromTo(): merges into toProps (the 100% endpoint the user is editing).
 */
export function resolveConversionProps(
  anim: GsapAnimation,
  resolvedFromValues?: Record<string, number | string>,
): { fromProps: Record<string, number | string>; toProps: Record<string, number | string> } {
  if (anim.method === "set") {
    // A static hold becomes a keyframed `to` whose 0% and 100% both start at the
    // set's value — the visual is unchanged until the user edits a keyframe to
    // animate it. (The caller flips the call from `set` to `to` + adds a duration.)
    return { fromProps: { ...anim.properties }, toProps: { ...anim.properties } };
  }
  if (anim.method === "to") {
    const identity = buildIdentityMap(anim.properties);
    const fromProps = resolvedFromValues ? { ...identity, ...resolvedFromValues } : identity;
    return { fromProps, toProps: { ...anim.properties } };
  }
  if (anim.method === "from") {
    const identity = buildIdentityMap(anim.properties);
    const toProps = resolvedFromValues ? { ...identity, ...resolvedFromValues } : identity;
    return { fromProps: { ...anim.properties }, toProps };
  }
  // fromTo(fromVars, toVars): anim.fromProperties = fromVars (0% state),
  // anim.properties = toVars (100% state). resolvedFromValues contains the
  // current DOM position from a drag — it represents the NEW destination, so
  // it merges into toProps (the 100% endpoint the user is editing), NOT into
  // fromProps. This is intentional and not inverted.
  const toProps = resolvedFromValues
    ? { ...anim.properties, ...resolvedFromValues }
    : { ...anim.properties };
  return { fromProps: { ...(anim.fromProperties ?? {}) }, toProps };
}

// ── Arc path serialization helpers (shared by recast + acorn writers) ─────────