Basic JavaScript - Testing Objects for Properties

JavaScript
1

Tell us what’s happening:
Describe your issue in detail here.
I’m not understanding the error it is showing and what to rectify here ??
Your code so far

function checkObj(obj, checkProp) {
  // Only change code below this line
  // return "Change Me!";
if(obj.hasOwnProperty("checkProp")) {
  return obj["checkProp"];
}
else {
  return "Not Found";
}
  // Only change code above this line
}

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36

Challenge: Basic JavaScript - Testing Objects for Properties

Link to the challenge:

1 Like
2

Can you explain, what are you trying to do over here?

3

The line above is asking if there is a property named checkProp in the object, when the line should be checking if there is a property with the name that is the same as the value of the checkProp parameter.

Do you understand the difference?

4

If checkProp property exists in the object then return the value of the property checkProp else return “Not Found”

5

If these are the arguments passed to the function.

checkObj({gift: "pony", pet: "kitten", bed: "sleigh"}, "gift")

You should be checking whether the property gift exists in the object {gift: "pony", pet: "kitten", bed: "sleigh"}

But you are always checking whether the property checkProp exists in any given object.

This is because you are not using the parameter checkProp anywhere in your function.

6

Sorry, I’m not understanding how to use “checkProp” and where is it asked to use it ?!

7

For this to evaluate to true, the following object would have to be passed as the first argument to the function:

{gift: "pony", pet: "kitten", checkProp: "some value"}
8

Then you should review the previous challenges below:

9

oh okay, where could i run these codes and try manipulating it for my understanding ?

10

Yeah, I’ll go through them now:)

11

obj.hasOwnProperty(“checkProp”)

"checkProp" means a string. It will check for a specific property named checkProp.

obj.hasOwnProperty(checkProp)

checkProp means a variable. It will check for a property associated with the argument checkProp.

1 Like
12

Yeah, I made that change but unable to figure out why it isn’t passing for 3 cases.

// Only change code below this line
// return “Change Me!”;
if(obj.hasOwnProperty(checkProp)) {
return obj.checkProp;
}
else {
return “Not Found”;
}

// Only change code above this line
}

It worked for obj[checkProp]; instead of obj.checkProp;

13

Dot notation will not work with variables. When you say obj.checkProp its looking in obj for a property named “checkprop”. But you want to use the value stored in checkProp to check if its in obj, so you have to use bracket.

1 Like
14

Yes, what @Lego_My_Eggo said.

When accessing properties with dot notation, you need to use brackets when the property name is a variable.

It’s just a Javascript rule.