Testing Objects for Properties dot notation not working

JavaScript
1

Tell us what’s happening:
This code works, but I don’t know why dot notation doesn’t work in this instance. Can anyone explain?

Your code so far

// Setup
var myObj = {
  gift: "pony",
  pet: "kitten",
  bed: "sleigh"
};

function checkObj(checkProp) {
  // Your Code Here
  myObj.hasOwnProperty(checkProp);
  if (myObj.hasOwnProperty(checkProp) == true) {
    return myObj[checkProp];   //why doesn't dot notation work here: myObj.checkProp; ??
  } else {
  return "Not Found";
  }
}

// Test your code by modifying these values
checkObj("gift");

Your browser information:

Your Browser User Agent is: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:59.0) Gecko/20100101 Firefox/59.0.

Link to the challenge:
https://www.freecodecamp.org/challenges/testing-objects-for-properties

2

Review Accessing Objects Properties Using Dot Notation and Accessing Objects Properties with Bracket Notation:

There are two ways to access the properties of an object: the dot operator (.) and bracket notation ([]), similar to an array.
The dot operator is what you use when you know the name of the property you’re trying to access ahead of time.

3 Likes
3

So since the variable that represents the property needing to be accessed is not specific, only bracket notation would work in this instance? Thank you for the quick response.

4

You got it!

5

Looks like I took too long posting this, but I will just leave this here just in case it still helps.

Dot notation is useful for grabbing key-value pairs out of an object.

var myObj = {
  keyTwo: valueOne,
  keyOne: valueTwo,
  keyThree: valueThree
}
console.log(myObj.keyOne);  // outputs 'valueOne'
console.log(myObj.keyTwo);  // outputs 'valueTwo'
console.log(myObj.keyThree);  // outputs 'valueThree'

However, what if I am trying to reference key-values through a variable?

var thisVariable = keyOne;
console.log(myObj.thisVariable);  // there is no key 'thisVariable' in 'myObj'
console.log(myObj[thisVariable]);  // outputs 'valueOne' as expected

Bracket notation saves the day as the thisVariable expands into keyOne. Bracket notation is also needed if your key values have spaces in them.

1 Like
6

Both responses make this very clear. Thank you both.

7

Thanks ArielLeslie. I’ve been wondering about this 5 minutes ago.

8

thank u so much it helps me