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JavaScript JavaScript Basics (Retired) Creating Reusable Code with Functions Giving Information to Functions

Posted by Richard Otabil
Richard Otabil
Courses Plus Student 603 Points

I have a question . is it possible to call one parameter of a function and use it? am just curious .

i am learning about javascript functions .

I learnt that i can add parameters to a functions .

so eg. if i have to display items from a database (i am using a phonegap framework to build a mobile app) , and i want to call some items from a function like this -

function channeldetails (name , image, category , description ) {

}

is there a way i can call each one of them if i have a block of code in the function?

2 Answers

Jaco Burger
Jaco Burger
20,807 Points
Jaco Burger
Jaco Burger
20,807 Points

Yes it is, you're talking about a default parameter. But I think it's better to have a fallback so to speak, so inside your function you can have something like

... { if (description === undefined) { description = 0; } }

Somebody correct me if I'm wrong :)

Robert Richey
PLUS
Robert Richey
Courses Plus Student 16,352 Points
Robert Richey
Robert Richey
Courses Plus Student 16,352 Points

Hi Richard,

I'm unclear on your question, so I'll do my best to explain function parameters. They are variables that are local to the function and are initialized when the function is called by passing in arguments.

var width = 3;
var height = 4;

// functions are defined with parameters
function areaRectangle(a, b) {
  return a * b;
}

// functions are called with arguments
var area1 = areaRectangle(width, height);  // 12
var area2 = areaRectangle(5, 7);  // 35

// if you need a function with default parameters, consider the following
function areaCircle(p1) {
  var radius = p1 || 1;
  return Math.PI * radius * radius;
}

var area3 = areaCircle();  // 3.14...
var area4 = areaCircle(2);  // 12.56...

Please let me know if this helps or not.

Cheers