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JavaScript JavaScript Basics (Retired) Creating Reusable Code with Functions Passing an Argument to a Function

brendon hanson
brendon hanson
6,191 Points
Posted by brendon hanson
brendon hanson
6,191 Points

Help Me With FUNCTIONS

SInce I started javascript I have absolutely no issues with anything except functions! For some reason i just simply don't understand them! could you please help me with this one and maybe give me an explanation that could help me understand it more...It's very frustrating!

script.js 
function returnValue(apple) {
  var echo = I dont know;
  return apple;

}

returnValue('Apples are good');
index.html 
<!DOCTYPE HTML>
<html>
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  <title>JavaScript Basics</title>
</head>
<body>
<script src="script.js"></script>
</body>
</html>
Iagor Moraes
Iagor Moraes
18,678 Points

My friend, you created a function called "returnValue" with a parameter "apple", inside that function you maked a mistake, you assigned a "echo" variable: "var echo = I dont know;" this is wrong, you are not receiving the apple parameter and putting to the "echo" variable, thats why your code broke, and you must put string in a double or single quote, your correct function above:

function returnValue(apple) {
  var echo = apple;

  return echo;
}

returnValue('Apples are good');

then the text "apples are good" will be printed. Hope you understands whats going on now.

1 Answer

Samuel Ferree
Samuel Ferree
31,722 Points
Samuel Ferree
Samuel Ferree
31,722 Points

A function is a special type of subroutine. Specifically, a function is a bit of code, that may accept input data (as parameters), and may return a single value.

Let's look at a super simple function

function add2(x) {
  return x+2;
}

var six = add2(4);
var eight = add2(six);

console.log(six) // prints '6'
console.log(eight) //prints '8'
console.log(add2(10)) //prints '12'

So the data passed in, is a single parameter, a number, that we can use in the function as the variable x. The function adds 2 to x, and returns the result. We capture this result in other parts of our program and use it by assigning it to a variable, or as in the last example, passing it into another function (console.log is a function).

Here are some more examples of functions

//Takes two parameters
function min(a, b) {
  if(a < b) { 
    return a;
  } else {
    return b;
  }
}

//Doesn't return anything
function printToConsole(x) {
  console.log(x);
}

Hope this helps.

brendon hanson
brendon hanson
6,191 Points
brendon hanson
brendon hanson
6,191 Points

Thanks for the help, I still don't fully understand but that helped me enough to finish the challenge thanks! I'm just gonna keep trying to get the hang of it