Creates a new array with the results of calling a function for every array element. It’s often used for rendering lists in ReactJS. What is ‘hoisting’ in JavaScript? Hoisting is a JavaScript mechanism where variables and function declarations are moved to the top of their containing scope during the compile phase. What is ‘this’ keyword in JavaScript? ‘this’ is a reference variable in JavaScript that refers to the context of the function where it is used. Its value is determined by the invocation context of the function it is used in.

What are JavaScript data types? JavaScript data types include Number, String, Boolean, Null, Undefined, Object, and Symbol. What is asynchronous programming, and why is it important in JavaScript? Asynchronous programming means that the engine runs in an event loop. When a blocking operation is needed, the request is started, Email List and the code keeps running without blocking for the result. When the response is ready, an interrupt is fired, which causes an event handler to be run, where the control flow continues. In this way, JavaScript engines work in a non-blocking (asynchronous) manner, which makes them very efficient.



JavaScript uses the Fetch API or the older XMLHttpRequest for creating AJAX requests. These AJAX requests allow for asynchronous communication with servers for performing CRUD operations without page reloads, creating a smoother user experience. What is a JavaScript class and how is it used? JavaScript classes are a type of function that serve as a blueprint for creating objects. They encapsulate data with code to work on that data and are mostly used for object-oriented programming in JavaScript. How is inheritance achieved in JavaScript? Inheritance in JavaScript can be achieved through the “prototype” system.


_________________
Email List