Function applyOne

packages/sdk/src/engine/apply-patches.ts:144–290

(parsed: ParsedDocument, patch: JsonPatchOp, p: ParsedPath)

// fallow-ignore-next-line complexity
function applyOne(parsed: ParsedDocument, patch: JsonPatchOp, p: ParsedPath): void {
  switch (p.type) {
    case "style": {
      const el = p.id ? findById(parsed.document, p.id) : null;
      if (!el || !p.prop) return;
      if (patch.op === "remove") {
        setElementStyles(el, { [p.prop]: null });
      } else {
        setElementStyles(el, { [p.prop]: String(patch.value) });
      }
      break;
    }

    case "text": {
      const el = p.id ? findById(parsed.document, p.id) : null;
      if (!el) return;
      if (patch.op === "remove") {
        setOwnText(el, "");
      } else {
        setOwnText(el, String(patch.value ?? ""));
      }
      break;
    }

    case "attribute": {
      const el = p.id ? findById(parsed.document, p.id) : null;
      if (!el || !p.prop) return;
      if (patch.op === "remove") {
        el.removeAttribute(p.prop);
      } else {
        el.setAttribute(p.prop, String(patch.value ?? ""));
      }
      break;
    }

    case "timing": {
      const el = p.id ? findById(parsed.document, p.id) : null;
      if (!el || !p.field) return;
      if (p.field === "start") {
        if (patch.op === "remove") el.removeAttribute("data-start");
        else el.setAttribute("data-start", String(patch.value));
      } else if (p.field === "duration") {
        // Patch value is the data-duration value — set directly.
        if (patch.op === "remove") el.removeAttribute("data-duration");
        else el.setAttribute("data-duration", String(patch.value));
      } else if (p.field === "end") {
        // Patch value is the absolute data-end time — set directly, no re-derivation.
        if (patch.op === "remove") el.removeAttribute("data-end");
        else el.setAttribute("data-end", String(patch.value));
      } else if (p.field === "trackIndex") {
        if (patch.op === "remove") el.removeAttribute("data-track-index");
        else el.setAttribute("data-track-index", String(patch.value));
      }
      break;
    }

    case "hold": {
      const el = p.id ? findById(parsed.document, p.id) : null;