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Introduction to ES6 modules In the early days, JavaScript initially served small scripting tasks that provided interactivity to web pages. Nowadays, JavaScript has evolved to power complete applications in browsers and servers (Node.js). To handle this growth, it is necessary to modularize JavaScript code into modules and make them reusable across applications. ES6 introduced the…

A call stack is a way for the JavaScript engine to keep track of its place in code that calls multiple functions. It has the information on what function is currently being run and what functions are invoked from within that function… Also, the JavaScript engine uses a call stack to manage execution contexts: The call stack works…

Let’s start with the following example: let x = 10; function timesTen(a){ return a * 10; } let y = timesTen(x); console.log(y); // 100 Code language: JavaScript (javascript) In this example: Behind the scenes, JavaScript does many things. in this tutorial, you will focus on execution contexts. When the JavaScript engine executes the JavaScript code,…

In computer programming, reflection is the ability of a program to manipulate variables, properties, and methods of objects at runtime. Prior to ES6, JavaScript already had reflection features even though they were not officially called that by the community or the specification. For example, methods like Object.keys(), Object.getOwnPropertyDescriptor(), and Array.isArray() are the classic reflection features. ES6 introduces a new global object called Reflect that…

A JavaScript Proxy is an object that wraps another object (target) and intercepts the fundamental operations of the target object. The fundamental operations can be the property lookup, assignment, enumeration, function invocations, etc. Creating a proxy object To create a new proxy object, you use the following syntax: let proxy = new Proxy(target, handler); Code language: JavaScript…

#1: Variable scopes The var variables belong to the global scope when you define them outside a function. For example: var counter;Code language: JavaScript (javascript) In this example, the counter is a global variable. It means that the counter variable is accessible by any function. When you declare a variable inside a function using the var keyword, the scope of the variable is…

ES6 provides a new way of declaring a constant by using the const keyword. The const keyword creates a read-only reference to a value. const CONSTANT_NAME = value;Code language: JavaScript (javascript) By convention, the constant identifiers are in uppercase. Like the let keyword, the const keyword declares blocked-scope variables. However, the block-scoped variables declared by the const keyword can’t be reassigned. The variables declared…

In ES5, when you declare a variable using the var keyword, the scope of the variable is either global or local. If you declare a variable outside of a function, the scope of the variable is global. When you declare a variable inside a function, the scope of the variable is local. ES6 provides a new way of declaring…