How to properly delete object from array?

Question

I have a javascript function which delete object from object array:

function RemoveFilter(filtArray,filtName) {
    var filtCount = filtArray.length;

    ...
    ...

    for (var i = 0; i < filtCount; i++) {
        var filter = filtArray[i];
        if (filter != undefined && filter.name == filtName) {
            delete filtArray[i];
        }
    }

    ...
    ...
}

It's works but I got a big problem. Instead of removing object completelly, it leaves undefined on its place (that why I have filter != undefined in my if).

So basically, if I am adding something after removal, I have not only new values but also those undefiled, and array is growing.

Probably my choise of object removing is poor but, how can I deal with this problem? Considering that filtArray[i].remove not working at all.

For such a task an elegant solution, if you're using jQuery, would be using the .filter prototype as an alternative to the splice method. Is your array an associative array? Check georg's solution below! — briosheje
– briosheje, Commented Mar 23, 2015 at 11:49

georg · Accepted Answer · 2015-03-23 12:15:52Z

3

Instead of trying to modify an array in place, which is messy and error prone, just create a new array using filter and assign it back to the original:

myArray = myArray.filter(function(item) {
    return item.name !== name
});

edited Mar 23, 2015 at 12:15

answered Mar 23, 2015 at 11:48

georg

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2 Comments

briosheje Over a year ago

Oh darn, just said that above in the comments. This is a much cleaner solution instead of a .splice and it also is way more versatile, due to the fact that you might slightly edit that filter in order to delete more items providing a regular object. Bump that solution! +1

Olegs Jasjko Over a year ago

Thank you! This was the best one. No questionable splice and also allows to throw to oblivion "for".

nikjohn · Accepted Answer · 2015-03-23 11:57:28Z

2

You want to use splice() instead of delete. That should work.

var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.splice(2, 0, "Lemon", "Kiwi");

will give:

Banana,Orange,Lemon,Kiwi,Apple,Mango

If you don't want to add new elements while removing others, you might wanna do this;

fruits.splice(2, 1);

The result of fruits will be:

Banana,Orange,Lemon

Shamelessly copied from W3Schools

In your case,

function RemoveFilter(filtArray,filtName) {
    var filtCount = filtArray.length;
    for (var i = 0; i < filtCount; i++) {
        var filter = filtArray[i];
        if (filter != undefined && filter.name == filtName) {
            filtArray.splice(i,1);
        }
    }
}

This will remove the i-th object and not leave an undefined hanging there.

edited Mar 23, 2015 at 11:57

answered Mar 23, 2015 at 11:43

nikjohn

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4 Comments

Anthony Grist Over a year ago

An example that actually uses splice to remove items rather than insert new ones might be more useful.

Olegs Jasjko Over a year ago

Em and how it supposed to help? As I see in your example, it add new values and not removes them (also - how to do this in array?). Also, doit it update original array or what?

nikjohn Over a year ago

@OlegsJasjko, check now. I've added your scenario

nikjohn Over a year ago

@Olegs Corrected a mistake with the splice statement. Check now.

Saad · Accepted Answer · 2015-03-23 12:00:03Z

0

Using splice() is generally the way to go, and you can make it neat by doing something like this:

function removeFilter(filtArray, filtName) {
  var index = filtArray.indexOf(filtName);
  filtArray.splice(index, 1);
}

You can read more about splice() here.

EDIT:

To show you an example:

var dog = {name: 'Spot', type: 'Dog'}; 
var cat = {name: 'Meow', type: 'Cat'}; 
var animals = [dog, cat];

removeFilter(animals, dog); // -> Removes the dog object from the array

console.log(animals) // -> Only has the cat object remaining

edited Mar 23, 2015 at 12:00

answered Mar 23, 2015 at 11:47

Saad

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