Copy Javascript object array value

Question

from a dropdown I'm selecting an array from a javascript object:

$("#selector").change(function() {
    let array = [];
    Object.values(group[$("#selector").val()]).forEach(x => array.push(x));
    console.log(`Group: ${$("#selector").val()}, Array: ${array}`);
});

against an array such as:

let group = {
LocationA: [
{
        name: "A",
        length: 11,
        width: 9,
        height: 9
    },
    {
        name: "B",
        length: 26,
        width: 6,
        height: 20
    },
    {
        name: "C",
        length: 16,
        width: 12,
        height: 14
    }
],
locationB: [{
        name: "S-10662",
        length: 32,
        width: 18,
        height: 12
    }...

But the array outputs as a list of [object Object], not an array. I'm having difficulty copying a value (which is an array) into an array. I've searched for such an example, I cannot find one here.

The main problem that you are experiencing is confusing an array with an object. Below is a good working solution, but I would recommend reading up on the difference to help you in the future. medium.com/@zac_heisey/objects-vs-arrays-42601ff79421 — imvain2
– imvain2, Commented Jun 25, 2020 at 19:15

Avinash Dalvi · Accepted Answer · 2020-06-25 19:12:44Z

1

Change this line to :

console.log(`Group: ${$("#selector").val()}  Array: `, samplearray);

Variable you can console like this for printing array can't concatenate.

let group = {
  LocationA: [{
      name: "A",
      length: 11,
      width: 9,
      height: 9
    },
    {
      name: "B",
      length: 26,
      width: 6,
      height: 20
    },
    {
      name: "C",
      length: 16,
      width: 12,
      height: 14
    }
  ],
  locationB: [{
    name: "S-10662",
    length: 32,
    width: 18,
    height: 12
  }]
};
$("#selector").change(function() {
  let samplearray = [];
  Object.values(group[$("#selector").val()]).forEach(x => samplearray.push(x));
  console.log(`Group: ${$("#selector").val()}  Array: `, samplearray);
  console.log(samplearray);
});

<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
</head>
<body>
<select id="selector">
<option value="locationB" >locationB</option>
<option value="LocationA" >LocationA</option>
</select>
</body>

answered Jun 25, 2020 at 19:12

Avinash Dalvi

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2 Comments

Jim from Princeton Over a year ago

excellent, thanks. I was struggling with that for some time!!

Avinash Dalvi Over a year ago

Don’t forget to upvote and accept if you feel this help you. You have enough reputation do the same

Pavlos Karalis · Accepted Answer · 2020-06-25 19:20:13Z

1

I don't think you need the forEach because you're already extracting the values as an array with Object.values; you can directly store it to your array variable:

    let array = Object.values(group[$("#selector").val()]);

That gives you an array of objects; with the forEach you were telling javascript to iterate through each of those objects, which isn't possible. If the goal was to also extract the values of those objects, then you could do:

$("#selector").change(()  => {
    let array = Object.values(group[$("#selector").val()]);
    console.log(array)
    let expandedArray = [];
    array.forEach(object => {
        expandedArray = [...Object.values(object), ...expandedArray]
    });
    console.log(expandedArray)
});

edited Jun 25, 2020 at 19:20

answered Jun 25, 2020 at 19:13

Pavlos Karalis

2,9761 gold badge9 silver badges15 bronze badges

1 Comment

Avinash Dalvi Over a year ago

You are right not required forEach because its already there. Upvoting this because you have right point.

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