Function waitForElementVisibility

build-system/tasks/visual-diff/verifiers.js:139–197

* Wait until the element is either hidden or visible or until timed out. * * Timeout is set to CSS_SELECTOR_RETRY_MS * CSS_SELECTOR_RETRY_ATTEMPTS ms. * * @param {!puppeteer.Page} page page to check the visibility of elements in. * @param {string} selector CSS selector for elements to wait on.

(
  page,
  selector,
  options,
  timeoutMillis
)

 *      error with the message value set to the CSS selector.
 */
async function waitForElementVisibility(
  page,
  selector,
  options,
  timeoutMillis
) {
  const waitForVisible = Boolean(options['visible']);
  const waitForHidden = Boolean(options['hidden']);
  if (waitForVisible == waitForHidden) {
    log(
      'fatal',
      'waitForElementVisibility must be called with exactly one of',
      "'visible' or 'hidden' set to true."
    );
  }

  const startTime = Date.now();
  do {
    const elementsAreVisible = [];

    for (const elementHandle of await page.$$(selector)) {
      const boundingBox = await elementHandle.boundingBox();
      const elementIsVisible =
        boundingBox != null && boundingBox.height > 0 && boundingBox.width > 0;
      elementsAreVisible.push(elementIsVisible);
    }

    if (elementsAreVisible.length) {
      log(
        'verbose',
        'Found',
        cyan(elementsAreVisible.length),
        'element(s) matching the CSS selector',
        cyan(selector)
      );
      log(
        'verbose',
        'Expecting all element visibilities to be',
        cyan(waitForVisible),
        '; they are:',
        cyan(elementsAreVisible.join(', '))
      );
    } else {
      log('verbose', 'No', cyan(selector), 'matches found');
    }
    // Since we assert that waitForVisible == !waitForHidden, there is no need
    // to check equality to both waitForVisible and waitForHidden.
    if (
      elementsAreVisible.every(
        (elementIsVisible) => elementIsVisible == waitForVisible
      )
    ) {
      return true;
    }

    await sleep(CSS_SELECTOR_RETRY_MS);
  } while (Date.now() < startTime + timeoutMillis);
  throw new Error(selector);