Function createTestRenderer

packages/core/src/testing/renderer.ts:506–645

(opts: TestRendererOptions = {})

 * real update sequences without manual commit/layout plumbing.
 */
export function createTestRenderer(opts: TestRendererOptions = {}): TestRenderer {
  let prevRoot: RuntimeInstance | null = null;
  let allocator: InstanceIdAllocator = createInstanceIdAllocator(1);
  const defaultViewport = normalizeViewport(opts.viewport);
  const rendererTheme = normalizeTheme(opts.theme);
  const defaultFocusedId = opts.focusedId ?? null;
  const defaultTick = opts.tick ?? 0;
  const defaultMode = opts.mode ?? "test";
  const trace = opts.trace;
  const defaultTraceDetail = opts.traceDetail === true;
  let warnedTraceDetailWithoutTrace = false;
  let renderId = 0;

  const render = (vnode: VNode, renderOpts: TestRenderOptions = {}): TestRenderResult => {
    const startedAt = Date.now();
    renderId += 1;

    const viewport = normalizeViewport(renderOpts.viewport ?? defaultViewport);
    const focusedId = renderOpts.focusedId === undefined ? defaultFocusedId : renderOpts.focusedId;
    const tick = renderOpts.tick ?? defaultTick;
    const theme = normalizeTheme(renderOpts.theme ?? rendererTheme);
    const traceDetail = renderOpts.traceDetail ?? defaultTraceDetail;
    const mode = renderOpts.mode ?? defaultMode;
    if (traceDetail && !trace && !warnedTraceDetailWithoutTrace) {
      warnedTraceDetailWithoutTrace = true;
      console.warn(
        "[core/testing] createTestRenderer: traceDetail=true has no effect without a trace callback.",
      );
    }

    const commitStartedAt = Date.now();
    const committed = commitVNodeTree(prevRoot, vnode, { allocator });
    const commitMs = Date.now() - commitStartedAt;
    if (!committed.ok) {
      throw new Error(
        `createTestRenderer: commit failed: ${committed.fatal.code}: ${committed.fatal.detail}`,
      );
    }
    prevRoot = committed.value.root;

    const layoutStartedAt = Date.now();
    const layoutTree = layoutRootOrThrow(prevRoot, viewport);
    const layoutMs = Date.now() - layoutStartedAt;
    const builder = new RecordingDrawlistBuilder();

    const drawStartedAt = Date.now();
    renderToDrawlist({
      tree: prevRoot,
      layout: layoutTree,
      viewport,
      focusState: Object.freeze({ focusedId }),
      builder,
      theme,
      tick,
    });
    const drawMs = Date.now() - drawStartedAt;

    const ops = builder.snapshotOps();