Explain Closures in modern javascript [duplicate] - javascript

This question already has answers here:
How do JavaScript closures work?
(86 answers)
Closed 2 years ago.
I have been learning javaScript lately but I got confused in understanding the concept of closures.How does JavaScript closures actually work ?

A  closure gives you access to an outer function’s scope from an inner function
for more info you can follow this link-
http://sleeplessgeek.blogspot.com/2009/12/so-what-are-these-closure-thingys.html

Related

Reason behind strange iterator syntax on Arrays [duplicate]

This question already has answers here:
What is the motivation for bringing Symbols to ES6?
(7 answers)
Why do you access Symbol.iterator via brackets?
(3 answers)
Closed 3 years ago.
I recently learned that to get an iterator from an Array, you have to access it using syntax that I have never seen before: let iterator = myArray[Symbol.iterator]()
It seems to me that implementing Array.prototype.getIterator() would have been a more idiomatic way to go, but I must be oversimplifying or just not understanding the significance of accessing this property of arrays in this particular way.
In attempting to deepen my understanding of the inner workings of JavaScript I was hoping someone could explain this diversion from a more traditional syntax.

Problem with simple variable assignment in Javascript [duplicate]

This question already has answers here:
Are 'Arrow Functions' and 'Functions' equivalent / interchangeable?
(4 answers)
`this` is undefined in Dev Tools when using arrow function
(2 answers)
Closed 4 years ago.
Facing a Javascript problem that has to be simple. Going nuts.
I declare and assign a variable as usual: 'let that = this';
When running the code in the Chrome debugger, 'this' is defined and has a value, but 'that' remains undefined. I know that 'this' is fickle in Javascript, but we're speaking the line after the assignment.
Any idea of what would happen? This is in a quite simple event handler, don't see where there could be a trap.
I started using Flow and transpiling JS with Codekit. I have the impression that Chrome debugger has gone a bit unstable since, could it be related?
Many thanks!
Screenshot in Chrome debugger

How to use "this" inside a function for javascript, jquery, object oriented principle [duplicate]

This question already has answers here:
What does "this" mean in jQuery? [duplicate]
(6 answers)
Closed 6 years ago.
Can any help how to use "this" inside a function for javascript, jquery, php. Because it is little confusing me how to use it. can we "this" inside iteration for loop. Please explain me with simple example.
Thanks you for time.
This is well documented in the official js documentation.
link
This article explains even better link

Javascript function compiling? [duplicate]

This question already has answers here:
Why can I use a function before it's defined in JavaScript?
(7 answers)
Closed 10 years ago.
I have noticed that when coding in javascript, it doesn't matter if i declare the function before or after i call it. In other languages it will cause an exception, but when running javascript in chrome it works just fine. Is that only in chrome, or is that normal?
What you're seeing is function hoisting in action: http://elegantcode.com/2011/03/24/basic-javascript-part-12-function-hoisting

What is lambda? [duplicate]

This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
What is the difference between a 'closure' and a 'lambda'?
Hello everyone!
I'm a JavaScript developer. I know what is closure and how it works in JavaScript.
But today I see a new noun "lambda". What is lambda? It appears to be relevant to closure in JavaScript. What's the difference between lambda and closure in JavaScript?
Thank you!
Refer to Wikipedia:
In mathematical logic and computer science, lambda calculus, also written as λ-calculus, is a formal system for function definition, function application and recursion.
Look at Motivation, under Informal description

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