getBy

getBy is a family of query functions used in the DOM Testing Library and React Testing Library to retrieve a single element from the rendered DOM during tests. These are synchronous queries that throw an error when no element matches or when more than one element matches, helping to catch missing or ambiguous elements early in test runs.

Common variants include getByText, getByRole, getByLabelText, getByPlaceholderText, getByDisplayValue, getByAltText, and getByTestId. They reflect how users typically locate elements by visible text, accessible roles, labels, placeholder text, and other accessible attributes. If you need multiple elements, you should use the corresponding getAllBy... form. If an element may not be present, queryBy... returns null instead of throwing. For asynchronous scenarios, findBy... returns a promise that resolves when an element appears.

Usage considerations: getBy... queries model user interactions and accessibility semantics rather than relying on internal DOM structure. They are generally preferred over direct DOM selectors like querySelector in tests. In practice, prefer getByRole and getByLabelText for reliability and resilience to markup changes, and reserve getByTestId for cases where other selectors are not feasible. getBy is a core part of the Testing Library family and is widely used in component and integration testing to verify element presence and attributes.