Bharat Parenterals Interview Questions and Answers

Optimizing components in React involves using shouldComponentUpdate, memoization, lazy loading, and code splitting.

• Use shouldComponentUpdate to prevent unnecessary re-renders

• Memoize expensive calculations using useMemo or useCallback

• Implement lazy loading for components that are not immediately needed

• Utilize code splitting to load only necessary components when required

Create a form using React for machine coding interview

• Use React components to create form elements

• Handle form submission using state and event handlers

• Validate form inputs before submission

useMemo is used for memoization of values, while useCallback is used for memoization of functions.

• useMemo is used to memoize a value and only recompute it when its dependencies change.

• useCallback is used to memoize a function instance and only re-create it when its dependencies change.

• Example: useMemo can be used to memoize the result of a complex computation, while useCallback can be used to memoize a callback function passed to a child component.

FlatList is optimized for long lists with dynamic data, while ScrollView is for small lists or content that needs to be scrolled.

• FlatList is more performant for long lists as it only renders the items that are currently visible on the screen.

• ScrollView is more suitable for smaller lists or content that does not need to be dynamically loaded.

• FlatList supports key extraction for efficient rendering, while ScrollView does not have built-in support for this.

• FlatList provides buil...read more

Hoisting is a JavaScript mechanism where variable and function declarations are moved to the top of their containing scope.

• Variable declarations are hoisted to the top of their scope but not their initializations.

• Function declarations are fully hoisted, meaning they can be called before they are declared.

• Hoisting can lead to unexpected behavior if not understood properly.