What the best way to compare indexes of an array in javascript?

Question

I'm trying to compare indexes of an array. However I'm not to sure I'm going about it correctly. My thoughts are:

let tempArray = [tempInfo1,tempInfo2];

if(tempArray[0] == tempArray[1]){
    console.log('true');
}else{
    console.log('false');
}

Am I headed in the right direction? Or is this completely off?

Essentially - I'm trying to make a 'matching game'. Clicking an element stores that element in a tempArray (tempInfo1), and clicking on a second element stores a second value in that array (tempInfo2). Then I'm trying to check if the values are the same - do something. If not do something else. Does this help?

This seems very counter intuitive, you should use objects or map instead — Pavlo, Aug 07 '18 at 21:08
`Am I headed in the right direction?` Unsure what you asking, so it's hard to say. — Keith, Aug 07 '18 at 21:08
You are not comparing indexed, you are comparing values, and by definition indexes of the same array must be different. — Emeeus, Aug 07 '18 at 21:09
do you like to compare each value and check if all values are the same? — Nina Scholz, Aug 07 '18 at 21:10
I'm trying to compare two values that are being stored in the same array - I take it thats a bad way to do it? Would it be better to split the array into two - and then compare those? — ab3d_work, Aug 07 '18 at 21:15
it is just an overhead instead of comparing the two values directly. **but** if you need to collect the values first, then it makes sense and all is fine. — Nina Scholz, Aug 07 '18 at 21:17
It might be better if you try to explain what problem your trying to solve, often example input & expected output come in very handy here. — Keith, Aug 07 '18 at 21:17
I add some more info on what I'm trying to accomplish. I hope it makes it more clear! — ab3d_work, Aug 07 '18 at 21:22

score 1 · Answer 1 · answered Aug 07 '18 at 21:32

To head you in the right direction

You are probably working with a 4x4 of elements.

Lets say an element looks like this

HTML

<div id="card" value="cat"></div>

JavaScript

let lastSelected = null;
document.getElementById('card', (event) => {
    if(event.target.value === lastSelected.value){
      // remove both elements
    } else {
      lastSelected = event.target
    }
});

score 0 · Answer 2 · answered Aug 07 '18 at 21:25

First as mentioned in comments you are comparing values. Indexes are just 0, 1, 2, 3, 4... If you know what resides in an index that might be an option.

and actually that can fail if you're comparing object (and arrays that are a special type of object.)

Imagine this:

  var arrayOfDifferentTypes = [
  {
    somekey: "value"
  },
  {
    somekey: "value"
  },
  [1, 2, 3, 4],
  [1, 2, 3, 4],
  "data",
  "data",
  18,
  18
];

console.log(arrayOfDifferentTypes[0] === arrayOfDifferentTypes[1]); // false
console.log(arrayOfDifferentTypes[2] === arrayOfDifferentTypes[3]); // false
console.log(arrayOfDifferentTypes[4] === arrayOfDifferentTypes[5]); // true
console.log(arrayOfDifferentTypes[6] === arrayOfDifferentTypes[7]); // true

As you can see it will fail. You can check this or this one for that kind of comparison.

hmmm ok. I think I'm going to have to take a different direction. Thank you kindly for the input! — ab3d_work, Aug 07 '18 at 21:30

score 0 · Answer 3 · answered Aug 07 '18 at 21:26

0

You are not comparing indices of the array and as per your description that you are trying to make matching game which matches first two values in array then YES you're headed in right direction but use === instead of == to compare the values.

answered Aug 07 '18 at 21:26

Jarnu Girdhar

98
5

What the best way to compare indexes of an array in javascript?

3 Answers3