Function handleSetStyle

packages/sdk/src/engine/mutate.ts:303–335

(
  parsed: ParsedDocument,
  ids: HfId[],
  styles: Record<string, string | null>,
)

// ─── Op handlers ────────────────────────────────────────────────────────────

function handleSetStyle(
  parsed: ParsedDocument,
  ids: HfId[],
  styles: Record<string, string | null>,
): MutationResult {
  const result: MutationResult = { forward: [], inverse: [] };
  for (const id of ids) {
    const el = resolveScoped(parsed.document, id);
    if (!el) continue;
    const old = getElementStyles(el);
    setElementStyles(el, styles);
    for (const [prop, value] of Object.entries(styles)) {
      // Normalize to the camelCase key the style map + patch grammar use. A
      // hyphenated op key ("transform-origin") otherwise misses the camelCase
      // store, so oldValue is always null → undo deletes/loses the prior value,
      // a removal skips its inverse patch entirely (DOM/patch-log desync), and
      // the patch path/override-set key diverge from the camelCase grammar.
      const key = toCamel(prop);
      const path = stylePath(id, key);
      const oldValue = old[key] ?? null;
      if (value !== null) {
        const p = scalarChange(path, oldValue, value);
        result.forward.push(p.forward);
        result.inverse.push(p.inverse);
      } else if (oldValue !== null) {
        const p = scalarDelete(path, oldValue);
        result.forward.push(p.forward);
        result.inverse.push(p.inverse);
      }
    }
  }
  return result;
}

function handleMoveElement(
  parsed: ParsedDocument,