Web / ReactJS Interview questions
Explain Redux Thunk.
Redux Thunk middleware allows you to write action creators that return a function instead of an action. The thunk can be used to delay the dispatch of action or to dispatch only if a certain condition is met. The inner function receives the store methods dispatch and getState as parameters.
An action creator that returns a function to perform asynchronous dispatch:
const INCREMENT_COUNTER = 'INCREMENT_COUNTER'; function increment() { return { type: INCREMENT_COUNTER, }; } function incrementAsync() { return (dispatch) => { setTimeout(() => { // Yay! Can invoke sync or async actions with `dispatch` dispatch(increment()); }, 1000); }; }
An action creator that returns a function to perform conditional dispatch:
function incrementIfOdd() { return (dispatch, getState) => { const { counter } = getState(); if (counter % 2 === 0) { return; } dispatch(increment()); }; }
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