Function waitForPaint

packages/internal-test-utils/ReactInternalTestUtils.js:259–287

(expectedLog)

// now because that's how untable_flushUntilNextPaint already worked, but maybe
// we should split these use cases into separate APIs.
export async function waitForPaint(expectedLog) {
  assertYieldsWereCleared(waitForPaint);

  // Create the error object before doing any async work, to get a better
  // stack trace.
  const error = new Error();
  Error.captureStackTrace(error, waitForPaint);

  // Wait until end of current task/microtask.
  await waitForMicrotasks();
  if (SchedulerMock.unstable_hasPendingWork()) {
    // Flush until React yields.
    SchedulerMock.unstable_flushUntilNextPaint();
    // Wait one more microtask to flush any remaining synchronous work.
    await waitForMicrotasks();
  }

  const actualLog = SchedulerMock.unstable_clearLog();
  if (equals(actualLog, expectedLog)) {
    return;
  }

  error.message = `
Expected sequence of events did not occur.

${diff(expectedLog, actualLog)}
`;
  throw error;
}

export async function waitForDiscrete(expectedLog) {
  assertYieldsWereCleared(waitForDiscrete);