InvalidStateError

InvalidStateError is the name of a DOMException used in web platform APIs to indicate that an operation cannot be performed in the object's current state. It is part of the standard set of DOMException error names used by APIs to signal state-related constraints.

The error is defined in the DOM specifications as a way for APIs to communicate that a requested action is not valid given the object's current condition. It is commonly used by stateful objects that must be in a particular state before certain operations are allowed.

When it occurs, a method or API call throws (or returns a rejected promise with) InvalidStateError because a precondition about the object's state is not satisfied. Examples include attempting to operate on an object that has not yet been initialized, has been closed, or is otherwise not in the required state; or trying to perform an action while a previous operation is still in progress. The specific state requirements depend on the API in question.

Representation and handling: In JavaScript, InvalidStateError is usually represented as a DOMException with the name property equal to "InvalidStateError." It may be observed via try/catch blocks or as a rejected promise in asynchronous APIs. Client code can check error.name to distinguish it from other error types and implement appropriate fallback or retry logic.

See also: DOMException, NotFoundError, NotAllowedError, NotSupportedError, ConstraintError.