JavaScript’s Undefined Explored

It sounds a simple concept, but how do you actually check that a variable or property in JavaScript really exists? What is the best way to do this? How do we cover all of the edge cases? First, let’s look at what is undefined…Overview of undefined The value of a variable is given a type, and there are several built-in native types in JavaScript:UndefinedNullBooleanStringNumberObjectReferenceetc…