Function waitFor

packages/internal-test-utils/ReactInternalTestUtils.js:43–90

(expectedLog, options)

}

export async function waitFor(expectedLog, options) {
  assertYieldsWereCleared(waitFor);

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

  const stopAfter = expectedLog.length;
  const actualLog = [];
  do {
    class="cm">// Wait until end of current task/microtask.
    await waitForMicrotasks();
    if (SchedulerMock.unstable_hasPendingWork()) {
      SchedulerMock.unstable_flushNumberOfYields(stopAfter - actualLog.length);
      actualLog.push(...SchedulerMock.unstable_clearLog());
      if (stopAfter > actualLog.length) {
        class="cm">// Continue flushing until we've logged the expected number of items.
      } else {
        class="cm">// Once we've reached the expected sequence, wait one more microtask to
        class="cm">// flush any remaining synchronous work.
        await waitForMicrotasks();
        actualLog.push(...SchedulerMock.unstable_clearLog());
        break;
      }
    } else {
      class="cm">// There's no pending work, even after a microtask.
      break;
    }
  } while (true);

  if (options && options.additionalLogsAfterAttemptingToYield) {
    expectedLog = expectedLog.concat(
      options.additionalLogsAfterAttemptingToYield,
    );
  }

  if (equals(actualLog, expectedLog)) {
    return;
  }

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

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

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