What is the Redux middleware signature?
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02
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Comprehensive Model Answer
Verified Solution
Middleware is written as three nested (curried) functions:
const exampleMiddleware = (store) => (next) => (action) => {
// store => { getState, dispatch }
// next => calls the next middleware in the chain (or the reducer if last)
// action => the action currently being dispatched
return next(action);
};
storegives access togetState()anddispatch().nextpasses the action along to the next middleware (or the root reducer, if this is the last middleware).actionis the action object being processed.
Middleware must call next(action) (or dispatch(...) for a different action) to keep the chain moving — forgetting to call next silently swallows every action.
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