# What is x in function(x)?

#1

I'm on "7. Search for a friend". For some time I had an error, and I found out what caused the error, but I don't understand why it doesn't work in the first place.

The first code doesn't work, but the second does. I can put anything into function(x) except for "friends". Why is that? In the previous exercise, when making a list, friends was acceptable inside "function(x)", but not in the search part. What's the difference?

``````    for (var x in friends) {
if(friends[x].firstName === "Steve") {
console.log(friends[x]);
return friends[x];
} else {
console.log("No match!");
}
}
};

versus....

var search = function (name) {
for (var x in friends) {
if(friends[x].firstName === "Steve") {
console.log(friends[x]);
return friends[x];
} else {
console.log("No match!");
}
}
};

``````

#2

### the FUNCTION talk

``````var myFunc = function( param1, param2) {
//Begin of  anonymous FUNCTION-BODY
//VARIABLE -myFunc- has an -anonymous function- assigned
//this -anonymous function- has 2 PARAMETERS param1 and param2
//param1 and param2 PARAMETERS are used
//as -local- VARIABLES throughout the FUNCTION-BODY

console.log( param1 + " and " + param2 ) ;

//End of anonymous FUNCTION-BODY
};``````

If you want to call/execute the anonymous function
you will have to add a pair of parentheses to the variable myFunc
like
myFunc();
As the anonymous function was defined
as having 2 parameters
you have to provide 2 arguments
in our case 2 string VALUES "Alena" and "Lauren"
like
myFunc("Alena","Lauren");

some quotes from the outer-world:

**argument is the value/variable/reference being passed in,
parameter is the receiving variable used within the function/block**

OR

**"parameters" are called "formal parameters",
while "arguments" are called "actual parameters".**

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

### function with 1 parameter using return-statement

``````var myFunction = function( param1 ) {
//Begin of FUNCTION-BODY
//myFunction =function= has 1 PARAMETER param1
//this param1 PARAMETER is used as a -local- VARIABLE
//throughout the FUNCTION-BODY

return param1;

//End of FUNCTION-BODY
};``````

you have defined a myFunction function
which takes 1 parameter param1
this param1 parameter is used
as a variable throughout the FUNCTION-BODY.

If you want to call/execute this myFunction function
and this myFunction function was defined
as having 1 parameter param1
you will have to provide 1 argument
in our case a "number VALUE" 4
myFunction( 4 );

some quotes from the outer-world:

**argument is the value/variable/reference being passed in,
parameter is the receiving variable used within the function/block**

OR

**"parameters" are called "formal parameters",
while "arguments" are called "actual parameters".**

#### ============================================

As you are using the return-statement in your myFunction function
you will only get a return-value no-display.
You can however capture this return-value in a variable
and then use the console.log()-method to do a display.

``````var theResult = myFunction( 4 );
console.log( theResult );``````

OR directly

``console.log( myFunction( 4 ) );``

#3

``````var search = function (name) {
//you have used =name= as PARAMETER
// =name= PARAMETER is used as =local= VARIABLE
for (var x in friends) {
// here you reach out to the =global= VARIABLE =friends=
// =friends= VARIABLE was defined OUTSIDE of the function-scope
if(friends[x].firstName === name) {
//here you wanted to compare the =firstName= PROPERTY-VALUE
//with the =name= VARIABLE
console.log(friends[x]);
return friends[x];
}
//imagine you would have a data-collection of 100 friends
// you would get 60 "No match!"
//else {
//    console.log("No match!");
//}
}
//if you reach this line
// you did not encounter the =return= statement
console.log("No match!");
};``````

Now if you call the search =function=
you will have to provide an argument
like
`search("Steve")`

#4

Beautiful. That was all extremely helpful. I feel like I understand functions a lot more now. The definitions of parameters and arguments finally clicked for me too. Thank you.

#5