orenaksakal

Let & Const in ES6

Because most of us know what are the differences between let const and var I would like to go a bit deeper and talk about what I have learned while studying how this simple code block gets evaluated "var foo = 'bar';".

Quick info

Javascript is a compiled language with these 3 layers

1. Engine: Responsible of compilation and execution, entire start to end life of the program.
2. Compiler: Parses the given tokens and generates the code to be read by machine.
3. Scope: Contains the lookup schema/list for all the declarations also creates accessablity map and rules for declarations

orenaksakal

Default Parameters

WHAT IS A PARAMETER ?

Parameter is a variable found in the function definition.
In compilation phase when we are on the line of a function definition with a parameter 
that parameter is registered to function's lexical scope as a local variable.

PARAMETER === LOCAL VARIABLE