HoldDownTimer

HoldDownTimer is a UI timing pattern used to detect when a user intentionally holds a control or key for a specified duration, triggering an action or series of actions. It is commonly employed to support long-press interactions, context menus, accessibility features, and other actions that should not be invoked by a brief tap.

Typical behavior involves starting a timer when a press begins (mouse down, touch start, or a focused key press) and monitoring the elapsed time. If the user releases before the threshold, the interaction is treated as a regular tap. When the threshold is reached, a hold event is emitted. Depending on the design, the hold may occur once after the initial threshold or continue to fire at regular intervals while the control remains held. This distinction yields a single-shot hold versus continuous auto-repeat behavior.

Implementation considerations include handling cancellation and edge cases. The timer should be cleared if the pointer is canceled, leaves the element, or if the input is interrupted by another event. Some implementations support multi-touch by counting only the primary pointer, while others may ignore additional touches. Accessibility guidance suggests enabling keyboard equivalents (for example, holding a key while activating the control) and providing visual feedback such as a progress indicator to communicate the hold state.

Common use cases include opening a context menu, enabling advanced options, adjusting a value by holding a button, and triggering irreversible actions with a deliberate hold. Developers may choose thresholds (for example, 400–800 milliseconds) and decide whether to emit a single event or continuous updates based on the intended user experience.