Rigved Technologies Software Engineer Interview Questions and Answers

A promise is an object representing the eventual completion or failure of an asynchronous operation.

• Promises are used in JavaScript to handle asynchronous operations.

• They can be in one of three states: pending, fulfilled, or rejected.

• Promises can be chained using .then() to handle success and failure callbacks.

• Example: Fetching data from an API returns a promise that resolves with the data or rejects with an error.

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

• Variable and function declarations are hoisted to the top of their scope.

• Only declarations are hoisted, not initializations.

• Function declarations take precedence over variable declarations.

Event loop is a mechanism in programming that allows for asynchronous execution of code by continuously checking for and handling events.

• Event loop is commonly used in JavaScript to handle asynchronous operations like setTimeout, setInterval, and AJAX requests.

• It allows for non-blocking I/O operations, ensuring that the program can continue running while waiting for I/O operations to complete.

• Event loop works by contin...read more