Javascript

a special JavaScript data type. In fact, Undefined is both a data type and value. JavaScript also has a global variable with the name undefined which has the value Undefined

d out the difference between let vs var vs const. Knowing the difference between them is makes it easier to decide what to use where and when.

This in JavaScript Call function   The Global object in JavaScript exposes useful variables & functions. It is known as the window in the browser & global in NodeJs. You can access the globalThis to access the global object irrespective of the environment in which JavaScript is run. Global Object The JavaScript has a built-in object,

JavaScript constants are variables, whose values cannot be modified after initialization. We declare them using the keyword const. They are block-scoped just like the let keyword. Their value cannot be changed neither they can be redeclared. Const keyword is part of the es2015 (es6) specification of the javascript.

JavaScript Keywords have a special meaning in the context of a language. They are part of the syntax of JavaScript. These are reserved words and we cannot use them as JavaScript Identifier names. Using them will result in a compile error.