Splice out data, unknown position

Question

I have a ToDo list, using localStorage... I need to be able to remove the item from the ToDo list... I try to use "dataArray.splice();" But the problem is I don't know how i can remove the object when the position is unknown...

function getTodoItems() {
    for (var i = 0; i < dataArray.length; i++) {
        if (!dataArray[i].listItem.length) return;
        var itemList = document.getElementById("my-todo-list");
        var list = document.createElement("li");
        itemList.appendChild(list);
        list.innerHTML = dataArray[i].listItem;
        var spanItem = document.createElement('span');
        spanItem.style.float = 'right';
        var myCloseSymbol = document.createTextNode('\u00D7');
        spanItem.classList.add("closeBtn");
        spanItem.appendChild(myCloseSymbol);
        listItems[i].appendChild(spanItem);
        close[i].onclick = function() {
            var div = this.parentElement;
            div.style.display = "none";
            console.log(dataArray);
        }
        var list = document.getElementsByTagName('li');
        list[i].onclick = function() {
            this.classList.toggle("checked");
        }
    }
}

You can look for the position first using daraArray.indexOf('myThing') perhaps. — Jason Allshorn, Dec 28 '17 at 17:01
Yes I am looping through, but since I don't know what object to remove from the todo list in advanced, the position is unknown... — Thomas Hermansen, Dec 28 '17 at 17:05
Your question is not clear. Which item do you need to delete in `dataArray`? — palaѕн, Dec 28 '17 at 17:09

score 1 · Answer 1 · answered Dec 28 '17 at 17:01

1

Then probably get its position:

 const position = dataArray.indexOf(/*whatever*/);
 dataArray.splice(position, 1);

answered Dec 28 '17 at 17:01

Jonas Wilms

132,000
20
149
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score 1 · Answer 2 · answered Dec 28 '17 at 17:03

1

You can get the position of the element using 'indexOf' let pos = dataArray.indexOf(element); dataArray.splice(pos,1)

answered Dec 28 '17 at 17:03

Sreenivas Shenoy

184
11

I tried this, and it is working sort of.. But it is deleting the last element... not the chosen or selected "item" – Thomas Hermansen Dec 28 '17 at 21:02

score 0 · Answer 3 · answered Dec 30 '17 at 18:54

0

IndexOf() wont work if you are trying to find the index of an entire object or array inside the array.

If you need to find the index of an entire object inside your array, you test each one's value to find out if it is the correct one. I would use findIndex();

Try this in your console:

var array = []; 
for (var i = 0; i < 10; i++ ){ array.push({item: i}) }
console.log('Current Array: ', array); 

var indexOfResult = array.indexOf({item: 3});
console.log('indexOf result: ',indexOfResult);

var findIndexResult = array.findIndex(object => object.item === 3);
console.log('findIndex result: ',findIndexResult)

answered Dec 30 '17 at 18:54

TJBlackman

1,895
3
20
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Thanks, but when using indexOf dont i then already know the position? – Thomas Hermansen Dec 30 '17 at 19:23
IndexOf only works on primitive data types. Since I know that you are trying to find the index of an object, I know you need to use findIndex(). Read this: https://stackoverflow.com/questions/41443029/difference-between-indexof-and-findindex-function-of-array – TJBlackman Dec 30 '17 at 19:33
I just tried it out and it works almost, but now it is removing the first element still not the chosen – Thomas Hermansen Dec 30 '17 at 19:47

Splice out data, unknown position

3 Answers3