Scope

def

• global scope
• variable declared outside of all functions
• function scope
• variable declared inside a function
• block scope
• variable declared inside a block by let or const

closures

def

• "Closure is when a function is able to remember and access its lexical scope even when that function is executing outside its lexical scope."

Pros

• encapsulation
• private data
• module

Curry

• convert a function with multiple arguments into a sequence of functions with single argument

Pros

• delay execution
• readable

Hoisting

move declare, assign to the top of the scope during complietion

can hoisting:

• function
• variable(let, const, var)

hoisting declare + assign: - function - not include var function

hoisting declare(can't use before assign): - let, const - reference error - var - undefined

can't hoisting:

• arrow function
• function expression javascript const a = function(){ console.log('a') }