Javascript - How to check the value of an array using a variable as the key

Question

Let's say I have a simple array like this:

const arr = {
    name: 'Lorem',
    age: 'Ipsum',
}

How would I check the value of name based on a variable that is, for example, set on click of a button? Here's what I tried:

const arr = {
    name: 'Lorem',
    age: 'Ipsum',
}

$('button').click(function(e) {
  e.preventDefault();
  var key = $(this).attr('data-key');
  // this:
  console.log(arr.key);
  // should return the same result as this:
  console.log(arr.name);
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<button data-key="name">Click Me</button>

arr[key] Also, that is an object, not an array.

iz_
– iz_

2021-08-12 21:34:30 +00:00
Commented Aug 12, 2021 at 21:34 — iz_
– iz_, Commented Aug 12, 2021 at 21:34
@iz_ thank you for both!

user13286
– user13286

2021-08-12 21:35:26 +00:00
Commented Aug 12, 2021 at 21:35 — user13286
– user13286, Commented Aug 12, 2021 at 21:35

Majed Badawi · Accepted Answer · 2021-08-12 21:34:32Z

2

Using the bracket notation:

const arr = { name: 'Lorem', age: 'Ipsum' };

$('button').click(function(e) {
  e.preventDefault();
  const key = $(this).attr('data-key');
  console.log(arr[key]);
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<button data-key="name">Click Me</button>

answered Aug 12, 2021 at 21:34

Majed Badawi

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Comments

Sidarth Nuthi · Accepted Answer · 2021-08-12 21:35:10Z

2

Arr.key takes the keyword "key" Literally, and does not replace your variable in with the key name. You need to add brackets like so to perform this action:

arr[key];

Doing it this way will replace the literal term "key" with the variable you have assigned to it.

answered Aug 12, 2021 at 21:35

Sidarth Nuthi

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