JavaScript - Insert & Remove a element in object

Question

I have a object.

var dl_items;

After a loop for inputing data:

dl_items[code] = itemObject;

I have a array:

dl_items : {
            "code_A" : { "index" : 1, "status" : 2, "name" : A_data},
            "code_B" : { "index" : 2, "status" : 0, "name" : B_data},
            "code_C" : { "index" : 3, "status" : 1, "name" : C_data},
            "code_D" : { "index" : 4, "status" : 2, "name" : D_data},
            "code_E" : { "index" : 5, "status" : 4, "name" : E_data}
           }

Now I want to remove "dl_items[code_D]" and insert it into after "code_A" (index 2) for result like :

 dl_items : {
            "code_A" : { "index" : 1, "status" : 2, "name" : A_data},
            "code_D" : { "index" : 4, "status" : 2, "name" : D_data},
            "code_B" : { "index" : 2, "status" : 0, "name" : B_data},
            "code_C" : { "index" : 3, "status" : 1, "name" : C_data},                
            "code_E" : { "index" : 5, "status" : 4, "name" : E_data}
            }

I try to use "delete" after using a loop to find index of code_D:

delete dl_items[code_D];

and it successful removed but how can i insert code_D into his new index ?

Edit : Thanks all everyone to help me understand more about array.

basically you show an object with objects. properties in objects have actually no order. you could use an array for ordered items. — Nina Scholz, Dec 02 '16 at 10:50
That's neither [JSON](https://stackoverflow.com/questions/2904131/what-is-the-difference-between-json-and-object-literal-notation) nor an [array](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array). `dl_items` is an [object](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object) — Andreas, Dec 02 '16 at 10:51
as @NinaScholz said, you can use an array, that will hold objects, that way you can easily just rewrite the index you want `array[3] = { status: 2, name: d_data}`, in javascript array is an object. — Yan Mayatskiy, Dec 02 '16 at 10:52
This has nothing to do with JSON. JSON is a way of encoding data in strings. — RemcoGerlich, Dec 02 '16 at 11:01
In JS, do not think in terms of "removing" or "inserting" elements into arrays. Instead, think in terms of creating a new array, with some elements added or removed. — , Dec 02 '16 at 11:06

Naor · Accepted Answer · 2016-12-02T11:30:06.900

1

Since object doesn't have an order, you need to convert your current implementation into array:

var dl_items = [];

When you need to add an item to the array:

dl_items.push({ code: code, item: itemObject });

Now, the similar data as array from your question is:

dl_items: [
            { code :"code_A", item: { index: 1, status: 2, name: "A_data" } },
            { code :"code_B", item: { index: 2, status: 0, name: "B_data" } },
            { code :"code_C", item: { index: 3, status: 1, name: "C_data" } },
            { code :"code_D", item: { index: 4, status: 2, name: "D_data" } },
            { code :"code_E", item: { index: 5, status: 3, name: "E_data" } },
          ]

In order to move the entry with code_D after the entry with code_A, use the following:

var codeDEntry = dl_items[3];
dl_items = dl_items
    .filter(function(entry) {
        return entry !== codeDEntry;
    })
    .splice(1, 0, codeDEntry);

Hope this helps!

edited Dec 02 '16 at 11:30

answered Dec 02 '16 at 11:04

Naor

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Can i ask why you used `unshift` ? In w3school, it said that `unshift` using to add a item to beginning of array. And i think your new array will be : D, A, B, C , E ? Please correct me if i was wrong :D – Zero-IT Dec 02 '16 at 11:26
Sorry, you completely right. I didn't read the question properly. I Fixed my answer. – Naor Dec 02 '16 at 11:30
Thank you. Now i will refactor the structure of my code a lot :D – Zero-IT Dec 02 '16 at 11:33
Glad I could help. – Naor Dec 02 '16 at 11:52

score 0 · Answer 2 · answered Dec 02 '16 at 10:57

0

You can make a temp var like this :

tempItem = dl_items.code_D;
dl_items.code_D = dl_items.code_B;
dl_items.code_B = tempItem;

answered Dec 02 '16 at 10:57

HichamEch

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score 0 · Answer 3 · answered Dec 02 '16 at 10:58

0

What you have here is an object, not an array. Therefore, there is no concept of an index here. You can map your object keys into an array as follows:

 let array = Object.keys(dl_items);

You can then reorder their positions.

answered Dec 02 '16 at 10:58

Amoolya S Kumar

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JavaScript - Insert & Remove a element in object

3 Answers3