forceUpdate

ForceUpdate is an imperative method used in some UI libraries, most notably React, to trigger a re-render of a component without changing its state or props.

In React class components, it is exposed as this.forceUpdate(). Calling this.forceUpdate() will cause the component to re-render and its subtree even if shouldComponentUpdate would normally prevent a render. It does not modify the component’s state or props. The update will run the render method and, depending on the version, lifecycle methods such as componentWillUpdate (legacy) and componentDidUpdate may be invoked.

Because forceUpdate bypasses the normal state/props change detection, it can lead to performance issues and makes the component’s rendering less predictable. It should be used sparingly, typically only when you are mutating data outside React’s managed state (for example, inspecting an external store or mutable object) and you need to refresh the UI to reflect those changes.

Alternatives include using setState to trigger re-renders, or converting to a functional component and using hooks to manage state. If you are using external stores, integrating with React via subscriptions or using useEffect/useReducer patterns is preferable.

Other frameworks provide similar functionality with different names, such as Vue’s vm.$forceUpdate(), which forces a re-render of the component by invalidating its render watchers.