Tx.transaction ​

Contract 2.0.0 · package sha256 a857eca95b35921109faf997094bb4192f12527d9d0fcd4be7e97f06425bad6e · generated from configurator-runtime.d.ts by services/onsite-scripter/scripts/build-contract-docs.mjs; edit the source, not this file.

Method of Tx · stable · since 2.0.0

transaction<T>(work: (sp: Tx) => T | Promise<T>, options?: SignalOption): Promise<TransactionReport<T>>;

A savepoint. Writes through sp are its own; its throw undoes only them, then rejects with that error: each path they wrote takes the latest write to it that no rolled-back savepoint made, or its value when the transaction opened (spec section 6.1, O7). A node, rule, item or connection that no surviving write created goes whole, with every path under it, and a surviving write under it is dropped (O7). It has no timeout, label or revision. sp closes when the savepoint settles: a later write through it throws HoloTransactionClosedError. An enlisted rejection its work never observed fails it, as a throw would. Outcome: 'staged', with value.

Options ​

Abort (signal) ​

This call is a write (SignalOption.signal, the kinds of call).

A write: before the commit point it rolls back and rejects AbortError; after it, no effect, except that a running camera move stops where the last frame drew it (CameraMoveOptions).

Through a tx the commit point is the transaction's: aborting a write still loading rejects AbortError and stages nothing (catch it: unobserved, it rolls the transaction back, spec section 6.1, O6); aborting one already staged unstages it, its paths keeping the latest other write to them as after a failed savepoint (O7), and its Promise stays resolved 'staged'.

Example ​

Imports: values (has, validate, the Holo*Error classes, the pure helpers) from @holostep-configurators/runtime-client, types from @holostep-configurators/runtime-client/contract, /math and /testing names from those entries; boot from the runtime module the root's loadRuntimeAtFloor resolves to. A type your page defines is your app's: declare it there, never import it from the package.

Compiled under the contract's strict settings (examples/declaration/05-Tx.transaction.ts):

import type { DeepReadonly, SceneModel, Session } from '@holostep-configurators/runtime-client/contract';
declare const session: Session;
declare const signal: AbortSignal;
// For an app whose scene model is its source of truth (a store app: spec section 11.2).
declare function withSofa(model: DeepReadonly<SceneModel> | null): SceneModel;
declare function nodeIdsOf(model: DeepReadonly<SceneModel> | null): ReadonlySet<string>;
declare const pillowUrl: string;
await session.transaction(async (tx) => {
  // inside `work`, read through `tx`, never `session`: a queued write's target reads unspecified
  const had = nodeIdsOf(tx.getSceneModel());
  const set = await tx.setSceneModel(withSofa(tx.getSceneModel()));
  // The sofa is all or nothing. A node the model already held lists its own failure too.
  if (set.problems.some((p) => p.code === 'asset-failed' && p.node && !had.has(p.node))) {
    throw new Error('sofa not loaded');    // everything rolls back; transaction() rejects it
  }
  try {
    await tx.transaction(async (sp) => {                   // an optional extra, as a savepoint
      await sp.collection('pillows').load(pillowUrl, { key: 'pillow-1' });
    });
  } catch {
    // The load failed: only the savepoint's writes were undone. The sofa still commits.
  }
}, { undo: 'Add sofa', origin: 'catalogue' });

Generic-API test (spec 3.1) ​