Prevent adding input to array a duplicate value in an object

Question

I have a field that inserts object to an array (tasks).

tasks[

description: "test",

id: "unique from date.now()" ]

How do i prevent from adding a same description value into my array.

<div class="container">
    <input id="list-input" />
    <input id="select-status" value="New" type="hidden"/>
    <button id="add">Add To List</button>
</div>

my script

var tasks = [];

$('#add').click(function() {
    var desc    = $.trim($('#list-input').val());
    var date    = Date.now(); //for unique value of id
    var strDate = date.toString();
    var id      = strDate.substring(strDate.length-6, strDate.length);

    item        = {};

    if (!desc) {
        item.id = "";
        alert("Input a description");
        return;
    }

    item.id          = id;
    item.description = desc;
    tasks.push(item);
}

i think that you should use an idArray and check each time that you push on tasks array a value if idArray includes the value before pushing it in tasks array — Milaci, Dec 19 '16 at 21:57

score 2 · Accepted Answer · answered Dec 19 '16 at 22:13

You CAN have array of objects, so not sure why you changed your initial tasks type? Anyway, you can do something like this:

var tasks = [];

$('#add').click(function() {
    var desc    = $.trim($('#list-input').val());
    var date    = Date.now(); //for unique value of id
    var strDate = date.toString();
    var id      = strDate.substring(strDate.length-6, strDate.length);

    item = {};

    if (!desc) {
        item.id = "";
        alert("Input a description");
        return;
    }

item.id          = id;
item.description = desc;

for(i=0;i<tasks.length;i++) {
if(tasks[i].description==desc) {
alert('In array!')
return;
}
}

tasks.push(item);    
 

 
 console.log(tasks); 
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="container">
    <input id="list-input" />
    <input id="select-status" value="New" type="hidden"/>
    <button id="add">Add To List</button>
</div>

So, just check if description value already exists in one of objects, inside array.

was doing exactly the same. but i placed my push to an else. thanks mate — Jorge, Dec 19 '16 at 22:25

score 0 · Answer 2 · edited May 23 '17 at 12:09

First off, your tasks array example is not a valid array i.e.:

[ description: "test", id: "unique from date.now()" ]

Are you meaning to enclose the elements in curly braces?:

[ 
  { description: "test", id: "unique from date.now()" }, 
  { description: "test2", id: "unique from date.now()" } 
]

If you want to make sure an object with a certain description doesn't already exist in the array, prior to adding the new object, you can loop the array and check for a previous duplicate before adding the new one in a similar way to this.

Prevent adding input to array a duplicate value in an object

2 Answers2