SUMMARY

Functions are useful and versatile tools in JavaScript programming. ECMAScript 6 introduces powerful syntax allowing you to wield them even more effectively.

• Function expressions are different from function declarations. Function declarations require names, while function expressions do not. A function expression without a name is also called an anonymous function.
• New in ES6, arrow functions are similar to function expressions, but with some important differences.
• Arguments and parameters in JavaScript functions are highly flexible. The arguments object, along with the new spread operator in ES6, allow for totally dynamic definition and invocation.
• Internally, functions expose a handful of objects and references that provide you information on how the function was invoked, where it was invoked, and what was originally passed to it.
• Engines will optimize functions with tail calls to preserve stack space.
• Behind the scenes, the closure's scope chain contains a variable object...