Wolong India Technology Interview Questions and Answers

useEffect is a hook in React that allows performing side effects in functional components.

• useEffect is used to perform side effects in functional components.

• It takes two arguments: a function and an array of dependencies.

• The function is executed after every render cycle.

• The array of dependencies is used to specify when the effect should be re-executed.

• An empty array [] means the effect should only be executed once, on component mount and unmount.

Use useState hook to manage state in functional components

• Import useState hook from React

• Declare state variable using useState hook

• Use state variable and setState function to update state

• Pass state variable and setState function as props to child components if needed

Hooks are a new feature in React 16.8 that allow you to use state and other React features without writing a class.

• Hooks are functions that let you use React state and lifecycle methods inside functional components

• They allow you to reuse stateful logic across multiple components

• useState is a hook that lets you add state to functional components

• useEffect is a hook that lets you use lifecycle methods in functional components

• useContext is a hook that lets you use context in func...read more

Reducer is a pure function that takes the previous state and an action, and returns the new state in Redux.

• Reducers specify how the application's state changes in response to actions sent to the store.

• They are pure functions that take the previous state and an action, and return the new state.

• Reducers should not modify the previous state, but return a new object if the state changes.

• Redux uses a single root reducer function that combines multiple reducers into one.

• Example: fu...read more

Redux is a predictable state container for JavaScript apps.

• Redux is a library for managing application state.

• It provides a central store for all the state in an application.

• State changes are made through actions, which are dispatched to the store.

• Reducers are pure functions that take the current state and an action, and return the new state.

• Selectors are functions that extract data from the state.

• Middleware can be used to intercept and modify actions before they reach the red...read more