Happiest Minds Technologies Senior Software Engineer Interview Questions, Process, and Tips

Closures are functions that have access to variables from their containing scope even after the scope has closed.

• Closures allow functions to access variables from their outer function even after the outer function has finished executing.

• They are commonly used in event handlers, callbacks, and asynchronous programming.

• Closures help in maintaining state in functional programming.

Virtual DOM is a lightweight copy of the actual DOM used for efficient updates in web development.

• Virtual DOM is a concept used in frameworks like React to improve performance by minimizing actual DOM manipulations.

• When changes are made to the virtual DOM, a comparison is done with the actual DOM to determine the minimal updates needed.

• This approach reduces the number of costly DOM operations, resulting in faster rende

Data types in JavaScript include number, string, boolean, object, function, undefined, and null.

• Number - represents numeric data, e.g. 10, 3.14

• String - represents textual data, e.g. 'hello', '123'

• Boolean - represents true or false values, e.g. true, false

• Object - represents complex data structures, e.g. { key: 'value' }

• Function - represents executable code, e.g. function() { }

• Undefined - represents a variable that has ...read more

React code for a simple counter

• Create a functional component for the counter

• Use useState hook to manage the count state

• Render the count value and buttons to increment and decrement the count