CODEWITHSUNDEEP
javascript
Dan
Dan

Reputation: 2174

javascript: how to remove data from array

From below code i tried removing data from array. Unfortunately Its not removing data from my array i.e ary , See if you can help me with this challange

var ary = [{"Force":"Force Converter"},{"Power":"Power Converter"}];

 function removeFav(n,v){ 
       var index = ary.indexOf(n);
       alert(index);
       if (index > -1) {
           ary.splice(index, 1);
        }
         alert("New updated Array:"+ary);
   }

Calling to remove as

removeFav("Power","Power Converter");  // this calls the above method

Upvotes: 0

Views: 554

Answers (3)

Legends
Legends

Reputation: 22672

Note: browser support for indexOf is limited, it is not supported in IE7-8.

Here is a demo Demo and below you can find the code again.

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>
    <script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
    <script>

        localStorage.clear();

        var ary = [];
        ary.push({ "Force": "Force Converter" })
        ary.push({ "Power": "Power Converter" });

        function contains(arr, k) {
            var doesContain = false;
            for (var i = 0, length = arr.length; i < length; i++) {
                var item = arr[i];
                if (item.hasOwnProperty(k)) {
                    doesContain = true;
                    break;
                }
            }
            return doesContain;
        }

        if (localStorage.getItem("testObject") != null) {
            alert("localstorage has item testobject");
            //Parse the retrieved value into an array
            ary = JSON.parse(localStorage.getItem('testObject'));
        }

        function setFavorite(k, v) {

            var obj = {};
            obj[k] = v;

            var hasItem = contains(ary, k);

            if (!hasItem) {
                ary.push(obj);
                // Put the object into storage
                localStorage.setItem('testObject', JSON.stringify(ary));
            }


            // Retrieve the object from storage
            var retrievedObject = localStorage.getItem('testObject');

            // Parse the retrieved value into an array
            var retrievedArray = JSON.parse(retrievedObject);

            // clear the ouput first
            $("#fab-id").html("");
            //iterate over the array which contains key-value pairs
            for (var i = 0; i < retrievedArray.length; i++) {
                var item = retrievedArray[i];

                var key = Object.keys(item)[0];
                var value = item[key];

                //----------BELOW CODE DOES NOT WORK PROPERLY----   
                $("#fab-id").append('<a>' + value + '</a><br/>');

            }
        }

    </script>
</head>
<body>
    <button id="btn">Click me!</button>
    <button id="btn2">Add another item!</button>

    <div id="fab-id"></div>

    <script>
        //adding a simple click event handler
        document.getElementById("btn").addEventListener("click", function () {
            //setFavorite("Power", "Power Converter");
            //setFavorite("Power", "Power Converter");
            setFavorite("propA", "X");
        });

        document.getElementById("btn2").addEventListener("click", function () {
            //setFavorite("Power", "Power Converter");
            //setFavorite("Power", "Power Converter");
            setFavorite("xyz", "blabal");
        });
    </script>

</body>
</html>

Upvotes: 1

Legends
Legends

Reputation: 22672

Your contains function is perfect. This should work for you, just use the name directly as property

function setFavorite(name, value){
 alert(contains(ary, value));

    var obj = {}; 
    obj.name = value; 
    alert(obj.name);
    ary.push(obj);
    alert(contains(ary, obj));

Upvotes: 1

Ian Kemp - SE killed by LLMs
Ian Kemp - SE killed by LLMs

Reputation: 29869

Your code is essentially calling ary.indexOf("Power"). But there is no element in ary with the index Power, hence why the call always fails. In fact, Array.indexOf() won't work for your scenario because it only works on simple types, not complex objects.

What you need to do is check for an object with the specified key in that array, and remove said object if it's found. For this you use the Object.hasOwnProperty()method:

function removeFav(key) { 
  for (var i = 0; i < ary.length; i ++) {
    // if the current array item has a property
    // that matches the specified one, remove that item
    if (ary[i].hasOwnProperty(key)){
      ary.splice(i, 1);
      return;
    }  
  }
}

Upvotes: 0

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