Function Scope
Having a hard time understanding function scope? I had, this is how I figured it out and now I am sharing it with you people.
What is Function?
When we wrap a bunch of code in braces {code}
so that we could use it as per our need. By simply calling the function name. It is not necessary for a function to have a name.
function sum( a, b ) {
return a + b;
}
In the above example, the sum is the name of the function, a and b are parameters
passed in and return
is what function would give you back when called. So let's call our sum ( )
with arguments
4, 6
sum( 4, 6 ) // 10
What is Scope?
In general, scope means looking at something carefully. Here, the scope is the address of a variable. Now let us see an example of Function Scope!
function warden( ) {
let prisoner = "I am in prison ๐ญ";
return prisoner;
}
let prisonerOne = "I am free ๐";
When we call the function warden ( )
the variable prisoner
is returned to us I am in prison ๐ญ
but not prisonerOne
because the function warden( )
do not know anything about prisonerOne
. Just for understanding purpose { }
curly braces are the boundaries of prison. Anything defined inside braces would be part of the prison and would be only accessible by warden( )
When we call the variable prisonerOne
we get I am free ๐
but when we call the variable prisoner
we get an error.
Uncaught ReferenceError: prisoner is not defined
This is because the variable prisoner
is scoped to the function warden( )
. The variable that is scoped to the function cannot be accessed outside the function.
If you read till here, thank you. Hope this blog helped you understanding Function Scope