Joshi Multispeciality Hospital Interview Questions and Answers

Hooks are functions that allow us to use state and other React features in functional components.

• useState is a hook that allows us to add state to functional components.

• useRef is a hook that allows us to create a mutable reference that persists across renders.

• useEffect is a hook that allows us to perform side effects in functional components.

• useState example: const [count, setCount] = useState(0);

• useRef example: const inputRef = useRef(null);

• useEffect example: useEffect(() =>...read more

Compose multiple HOCs with render props in a React component

• Create a render prop component that accepts a function as a prop

• Wrap the render prop component with HOCs

• Pass the function as a prop to the HOCs

• Use the function to render the component's content

• Example: withAuth(withTheme(RenderPropComponent))

Components are reusable UI elements in ReactJs. State is an object that stores data and controls a component's behavior.

• Components are like building blocks that can be combined to create complex UIs

• State is used to store and manage data within a component

• Changes to state trigger a re-render of the component

• State should be kept as minimal as possible to avoid performance issues

• Example: A button component can have a state that tracks the number of times it has been clicked

setTimeout, setImmediate and process.nextTick are Node.js functions used for asynchronous programming.

• setTimeout is used to execute a function after a specified amount of time has passed.

• setImmediate is used to execute a function immediately after the current event loop iteration.

• process.nextTick is used to execute a function at the beginning of the next event loop iteration.

• setTimeout and setImmediate are similar, but setImmediate has higher priority in the event loop.

• proces...read more

ReactJS life cycle refers to the series of methods that are invoked in the process of creating, updating and destroying a component.

• ReactJS life cycle consists of three phases: Mounting, Updating and Unmounting.

• Mounting phase includes methods like constructor, render, componentDidMount.

• Updating phase includes methods like shouldComponentUpdate, render, componentDidUpdate.

• Unmounting phase includes method componentWillUnmount.

• These methods help in managing the state and props o...read more

I used the Dijkstra's algorithm for finding the shortest path in my project.

• Implemented Dijkstra's algorithm to find the shortest path between nodes in a graph

• Used priority queue to optimize the algorithm

• Considered edge weights and node distances while calculating the shortest path

getDerivedStateFromProps() updates state based on props changes. getSnapshotBeforeUpdate() captures current state before update.

• getDerivedStateFromProps() is called before rendering and updates state based on changes in props.

• getSnapshotBeforeUpdate() is called after rendering but before updating the DOM. It captures current state before update.

• getDerivedStateFromProps() is a static method and should return an object to update state or null to indicate no update.

• getSnapshotBe...read more

Local Storage, Session Storage, and Cache are used to store data in the browser for faster access and better user experience.

• Local Storage: stores data with no expiration date and can be accessed across multiple windows and tabs

• Session Storage: stores data for a single session and is cleared when the session ends

• Cache: stores data temporarily to reduce server load and improve performance

• Examples: storing user preferences, caching images and scripts for faster page load