Javascript push Array items in Object

Question

I have the following issue for creating a object in Javascript

When a user clicks a button I want to push the sn_slab to the array slabs. But each serial_number is grouped by the batch_number.

The object should look something like this

    var Object = {
    'COFBP21018': {
        slabs: {
            0: 18765,
            1: 38947,
            ...
        }
    },
    'DEPOUS394O': {
        slabs: {
            0: 11006276,
            1: 11020446,
                    ...

        }
    },
    ..
}

my html looks like this

<a href=".." class="add_slab_to_array" data-batch_nr="COFBP21018" data-sn_slab="18765" />
<a href=".." class="add_slab_to_array" data-batch_nr="COFBP21018" data-sn_slab="38947" />
<a href=".." class="add_slab_to_array" data-batch_nr="DEPOUS394O" data-sn_slab="11006276" />
<a href=".." class="add_slab_to_array" data-batch_nr="DEPOUS394O" data-sn_slab="11020446" />

var block = {};
$('.add_slab_to_array').click(function(event) {
        event.preventDefault();

        var batch_nr = $( this ).attr('data-batch_nr');
        var sn_slab = $( this ).attr('data-sn_slab');

        // Create new object if batch_nr does not exists
        // ADD sn_slab to Array inside the Object with related batch_nr

      block[batch_nr] = {
           slabs: [],
           add: function(sn_slab) {
               this.slabs.push(sn_slab)
           }
       }

       block[batch_nr].add(sn_slab);

 });

The code above works, but my array slabs is always overridden.

And you realize that you're using the same key for several of those, so they will be overwritten when you use COFBP21018 twice etc. — adeneo
– adeneo, Commented Jun 10, 2014 at 14:20
Other than the mentioned problems, it works fine -> jsfiddle.net/8bvXz — adeneo
– adeneo, Commented Jun 10, 2014 at 14:22

ffflabs · Accepted Answer · 2014-06-10 14:23:18Z

2

It seems to me you're redefining the block object each time you click. You should instead check if it's set before proceeding.

block[batch_nr] = block[batch_nr] || {};

block[batch_nr].slabs = block[batch_nr].slabs || [];

block[batch_nr].add = block[batch_nr].add || function(sn_slab) {                         
            this.slabs.push(sn_slab);
           };

answered Jun 10, 2014 at 14:23

ffflabs

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1 Comment

Dancrumb Over a year ago

I don't think it needs to be this complicated... I think your diagnosis is correct, but I think the OP's code just needs the initial guard condition to prevent block[batch_nr] from being reinitialized

Arnaldo Ignacio Gaspar Véjar · Accepted Answer · 2014-06-10 14:23:42Z

0

Consider this

     block[batch_nr] = {
       slabs: [],
       add: function(sn_slab) {
           if (block[batch_nr]) {
               block[batch_nr].slabs.push(sn_slab)
           }
       }
   }

answered Jun 10, 2014 at 14:23

Arnaldo Ignacio Gaspar Véjar

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1 Comment

ffflabs Over a year ago

Very insightful answer!

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