Reading notes-JS Advanced Programming-seventh chapter function expressions

Closed Package	Functions that have access to variables in another function scope
anonymous functions	function has no Name
Use less closures	Because the closure carries the scope of the function that contains it, it consumes more memory than the other functions. Excessive use of closures can lead to excessive memory consumption, and we recommend that readers consider using closures only when absolutely necessary
Module mode
Enhanced Module mode
Privileged methods	Public methods that have access to private variables are called privileged methods
Block-level scopes
Implementing a single-instance privileged method

Reading notes-JS Advanced Programming-seventh chapter function expressions