What is Thunk?

In the context of Redux, a thunk is a function that wraps an expression to delay its evaluation. It is commonly used to delay the execution of asynchronous actions, such as API calls. Redux Thunk is a middleware that allows you to write action creators that return a function instead of an action. This function can then perform asynchronous operations and dispatch multiple actions, such as dispatching a 'request' action, then dispatching a 'success' or 'failure' action when the request completes. It is used to handle side effects.