JS Theory | Frontend Interview Survival Guide

📄️ Closure

Closure is a function that has access to its own scope, the scope of the outer function, and the global scope.

📄️ Data types

There are 8 basic data types in JavaScript:

📄️ Hoisting

Hoisting is a Javascript default behavior of moving functions, variables or classes declarations on top of the module/function level scope before executing the code.

The event loop is a single-threaded loop that monitors the call stack and the callback queue. If the call stack is empty, the event loop will take the first event from the queue and will push it to the call stack.

📄️ What happens when you type URL in browser

There are 6 general steps in this process:

📄️ call, apply, bind

fn.call(this, args)

📄️ Events: bubbling, capturing, propagation, delegation

This post explores the concept of event propagation in JavaScript, covering the three main phases: event capturing, event target, and event bubbling. We delve into how events travel through the DOM, the specifics of handling events during each phase, and the technique of event delegation for managing events efficiently on parent containers. This is essential reading for understanding how JavaScript interacts with web pages, making it crucial for both budding and seasoned developers.

📄️ Generators and Iterators in JavaScript

In JavaScript, iterators and generators are powerful tools that allow you to work with data in a more efficient and controlled way, especially when dealing with large datasets or complex iterations.

📄️ High Order Functions

A higher-order function is a function that accepts functions as parameters and/or returns a function.

📄️ Javascript Modules: AMD, CommonJS, ES6 Modules

JavaScript modules are a way to structure and organize code in JavaScript, allowing for easier management of dependencies and code reuse.

📄️ Memory Management and Garbage Collection in Javascript

Garbage collection in JavaScript is a form of automatic memory management. The garbage collector attempts to reclaim memory occupied by objects that are no longer in use by the program. Here’s a brief overview of how it works in JavaScript.

📄️ Pass by value and reference

In JavaScript, when you pass a variable to a function, you are passing a copy of the variable's value, not the variable itself. This concept is known as pass by value.

📄️ Promise, promise chain, promise.all vs promise.race

Promise

📄️ Prototypes

In Javascript prototype is a mechanism that allows objects to inherit properties and methods from other objects.

📄️ Pure and Impure functions

Pure function

📄️ How does a browser render a webpage?