🔥 Advanced JavaScript Concepts.😎

Hello everyone,👋

If you are new to JavaScript, it can be little bit of challenging to understand some core and Advance topics 🤷‍♂️. But don't worry keep your fingers crossed🤞 because in this article you'll get full information regarding Advanced JS Topics😁.

⚡ 1. Closures:

👉 MDN Def: A closure is the combination of a function bundled together (enclosed) with references to its surrounding state (the lexical environment).

Doesn't sound great to you???🤔 Don't worry. Stay tuned.🔥

So, Basically a function bind together with its lexical environment or lexical scope is known as Closer. Let's see what exactly is lexical scope.

⚡The word lexical refers to the fact that lexical scoping uses the location where a variable is declared. Nested functions have access to variables declared in their outer scope.

⚡ Running this code has exactly the same effect as the previous example of the x() function above.
⚡ What's different (and interesting) is that the displayName() inner function is returned from the outer function before being executed. The reason is that functions in JavaScript form closures. A closure is the combination of a function and the lexical environment within which that function was declared.

✅ Every closure has three scopes:

• Local Scope (Own scope).
• Outer Functions Scope.
• Global Scope.

✅ Let's say a function can access some variables of it's lexical environment or parent scope, the function actually remembers the reference of variable but it's value.

Let's look at the code:

Now you might have a bit understanding of Closures right.😎

✅ let's see some of uses of Closures:

• Module design pattern.
• Currying.
• Functions like once.
• Memoize.
• Maintaining state in Async World.
• setTimeouts.
• Iterators.
• and so on.......!.

{ .....
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... to be continued.
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