Remove Duplicates from Dropdown List By javascript only

I have a select dropdown field that is being created dynamically from a database . Due to the way this is being created it results in the dropdown having duplicate items and values.

<select id="locationList">
<option value="1">Andover</option>
<option value="2">Bishops waltham</option>
<option value="1">Andover</option>
<option value="3">Boscombe</option>
<option value="4">Bournemouth</option>
<option value="2">Bishops waltham</option>
<option value="4">Bournemouth</option>

</select>


Does anyone know if there is a way to use some code on the page which checks the dropdown for duplicates and removes duplicates from the menu only by Javascript No Jquery?

Thanks in advance,

Abhinav

2 Answers
2

Javascript has removeChild option, you can use it to remove duplicate value:

removeChild

var fruits = document.getElementById("locationList");

.slice.call(fruits.options)
.map(function(a)
if(this[a.value])
fruits.removeChild(a);
else
this[a.value]=1;

,);

<select id="locationList">
<option value="1">Andover</option>
<option value="2">Bishops waltham</option>
<option value="1">Andover</option>
<option value="3">Boscombe</option>
<option value="4">Bournemouth</option>
<option value="2">Bishops waltham</option>
<option value="4">Bournemouth</option>
</select>

Another option is to use the set as suggested here: alternatives or another alternative.

[ ...new Set([ ...<arg1>, ...<arg2> ]) ] for e.g.

[ ...new Set([ ...<arg1>, ...<arg2> ]) ]

var y = [ ...new Set([ ...[1, 2, 3, 4, 5], ...[3, 4, 5] ]) ]

var y = [ ...new Set([ ...[1, 2, 3, 4, 5], ...[3, 4, 5] ]) ]

// expected output: [ 1, 2, 3, 4, 5 ]

// expected output: [ 1, 2, 3, 4, 5 ]

Use the output to bind to the dropdown list.

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