Method batch

packages/sdk/src/session.ts:465–510

(fn: () => void, opts?: { origin?: unknown })

   */
  // fallow-ignore-next-line complexity
  batch(fn: () => void, opts?: { origin?: unknown }): void {
    const origin = opts?.origin ?? ORIGIN_LOCAL;
    this.batchDepth++;
    if (this.batchDepth === 1) {
      this.batchOrigin = origin; // only set on outermost entry
      this.batchOverridesSnapshot = { ...this.overrides };
    }
    let threw = false;
    try {
      fn();
    } catch (err) {
      threw = true;
      throw err;
    } finally {
      this.batchDepth--;
      if (this.batchDepth === 0) {
        if (!threw && this.batchForward.length > 0) {
          const event = buildPatchEvent(
            this.batchForward,
            [...this.batchInverse].reverse(),
            this.batchOrigin,
            this.batchOpTypes,
          );
          // Fire handlers before resetting batch state so that if a handler
          // throws the patch data (batchForward/batchInverse) is still intact
          // for callers that inspect it on error. The event was already built
          // from a snapshot so handler re-entrancy does not corrupt the event.
          this.patchHandlers.forEach((h) => h(event));
          this.changeHandlers.forEach((h) => h());
          this.resetBatchState();
        } else {
          if (threw && this.batchInverse.length > 0) {
            // Roll back: the dispatches inside the batch already mutated the
            // DOM. Without this, a throwing batch would leave the model in a
            // partial state with no patch trail to undo it.
            applyPatchesToDocument(this.parsed, [...this.batchInverse].reverse());
            this.overrides = { ...this.batchOverridesSnapshot };
            this.elementsCache = null;
          }
          this.resetBatchState();
          // Empty no-op batch: fire changeHandlers (parity with dispatch)
          if (!threw) this.changeHandlers.forEach((h) => h());
        }
      }
    }
  }

  private resetBatchState(): void {
    this.batchForward = [];