Scope
Scope:
is a place where we are look for things
Couple question
-
What are we looking for
Couple question
2. Which scope belongs to?
Execution context
Types of exuction
- Global
- Function
- Eval
Execution stack
Creation phase
Lexical Environment
Lexical Components
-
Environment Record
-
Reference to the outer environment
Types of Lexical Environment
-
Global
-
Functional
Types of Environment Record
-
Declarative
-
Object
Variable Environment
Hoisting
Solution
- Regular expression
- Parser
Closure
closure?
What is
closure is able to access its lexical scope
function can reference variables outside of itself
Types of scope
var:
function scoped
undefined when accessing a variable before it's declared
let:
block scoped
ReferenceError when accessing a variable before it's declared
const:
block scoped
ReferenceError when accessing a variable before it's declared
can't be reassignedTasks