findByText<E extends Element> function Async ByText Queries

Future<E> findByText<E extends Element>(Node container, dynamic text, { bool exact = true, NormalizerFn normalizer([ NormalizerOptions? ])?, String? selector, dynamic ignore = 'script', Duration? timeout, Duration interval = defaultAsyncCallbackCheckInterval, QueryTimeoutFn? onTimeout, MutationObserverOptions mutationObserverOptions = defaultMutationObserverOptions, })

Returns a future with a single element value with the given text content, defaulting to an exact match after waiting 1000ms (or the provided timeout duration).

If there is a specific condition you want to wait for other than the DOM node being on the page, wrap a non-async query like getByText or queryByText in a waitFor function.

Throws if exactly one element is not found within the provided container.

Prefer using ByRole queries when possible in order to query for elements in a way that most reflects how the user would interact with them.

Related: findAllByText

See: testing-library.com/docs/queries/bytext/

Example

The example below demonstrates the usage of the getByText query. However, the example is also relevant for getAllByText, queryByText, queryAllByText, findByText and findAllByText.

Read more about the different types of queries to gain more clarity on which one suits your use-cases best.

<a href="/about">About ℹ️</a>

import 'package:react/react.dart' as react;
import 'package:react_testing_library/matchers.dart' show isInTheDocument;
import 'package:react_testing_library/react_testing_library.dart' as rtl;
import 'package:test/test.dart';

main() {
  test('', () {
    // Render the DOM shown in the example snippet above
    final view = rtl.render(
      react.a({'href': '/about'}, 'About ℹ️'),
    );

    expect(view.getByText(RegExp(r'^About')), isInTheDocument);
  });
}

NOTE: render() supports React vDom elements / custom components created using either the

react or over_react packages.

The examples shown here use the react package since the react_testing_library does not have a direct dependency on over_react - but both libraries are fully supported.

Options

text

This argument can be set to a String, RegExp, or a Function which returns true for a match and false for a mismatch.

See the JS TextMatch docs for more details and examples.

exact

Defaults to true; matches full strings, case-sensitive. When false, matches substrings and is not case-sensitive. It has no effect on regex or function arguments. In most cases using a regex instead of a string gives you more control over fuzzy matching and should be preferred over exact: false.

normalizer

An optional function which overrides normalization behavior.

Before running any matching logic against text in the DOM, DOM Testing Library automatically normalizes that text. By default, normalization consists of trimming whitespace from the start and end of text, and collapsing multiple adjacent whitespace characters into a single space.

If you want to prevent that normalization, or provide alternative normalization (e.g. to remove Unicode control characters), you can provide a normalizer function. This function will be given a string and is expected to return a normalized version of that string.

NOTE: Specifying a value for normalizer replaces the built-in normalization, but you can call getDefaultNormalizer to obtain a built-in normalizer, either to adjust that normalization or to call it from your own normalizer.

See the JS TextMatch precision and JS TextMatch normalization docs for more details and examples.

selector

Set selector to a CSS selector that will narrow the scope of the existing query to only match element(s) that match the selector.

ignore

The ignore option accepts a query selector.

If the node.matches returns true for that selector, the node will be ignored. This defaults to 'script' because generally you don't want to select script tags, but if your content is in an inline script file, then the script tag could be returned.

If you'd rather disable this behavior, set ignore to false.

Async Options

timeout

How long to wait for the node to appear in the DOM before throwing a TestFailure, defaulting to 1000ms.

interval

How often the callback is called, defaulting to 50ms.

onTimeout

Is called if the timeout duration passes before the node is found in the DOM, and can be used to customize a TestFailure message.

mutationObserverOptions

The default values are:

{subtree: true, childList: true, attributes: true, characterData: true}

which will detect additions and removals of child elements (including text nodes) in the container and any of its descendants. It will also detect attribute changes. When any of those changes occur, it will re-run the callback.

Implementation

Future<E> findByText<E extends Element>(
  Node container,
  /*TextMatch*/ dynamic text, {
  bool exact = true,
  NormalizerFn Function([NormalizerOptions?])? normalizer,
  String? selector,
  /*String|bool*/ dynamic ignore = 'script',
  Duration? timeout,
  Duration interval = defaultAsyncCallbackCheckInterval,
  QueryTimeoutFn? onTimeout,
  MutationObserverOptions mutationObserverOptions = defaultMutationObserverOptions,
}) =>
    within(container).findByText<E>(text,
        exact: exact,
        normalizer: normalizer,
        selector: selector,
        ignore: ignore,
        timeout: timeout,
        interval: interval,
        onTimeout: onTimeout,
        mutationObserverOptions: mutationObserverOptions);