What Is a Closure in JavaScript
When working with closures you'll often hear the words "capture", "wrap", or "enclose". The entire idea behind a closure is to take a variable outside of the function and use that variable inside the function. A closure enables patterns for passing around functions that can manage buffers, caches, and values that can travel with the function.
John Lindquist: [0:00] Closure() is a function that accesses stuff not defined inside of it. If I defined a name up here of John and then console.logged out a name in here and called the closure, that would log out John. If I reassigned name to Mindy and then called the closure again, it logs out John then Mindy.
[0:27] If I set this to i and set this at , and then I logged out i++, every time I called the closure, we'll call it three times, you'll see, I'll zoom in, , 1, and 2. The huge difference here is if I was defined inside the closure and I hit Save, you'd see , , and because this is inside of the scope of this function and is recreated each time the function is called.
[0:59] It's the ability of functions to capture anything outside of the function and use that value each time the function is called, that make closure special.