Check if object exists in an array before pushing

Question

I have an empty array and a selectable tree, and every time when the user is checking or un-checking a node I'm pushing the node's id and if the checkbox is true or false.

But right now if the user will check and then un-check a node there will be two objects in the array of the same node how can i make sure that doesn't happen?

//creating empty array

var checkedItems = []; 

//(in kendo observable) on user selection I'm pushing the checked node to array

onItemChecked : function (e) {
    var node = e.sender.dataItem(e.node);
    checkedItems.push({Id: node.Id, IsChecked: node.checked});
},

Answer 1

You can, before pushing a new object, check the presence of an object that has that id.

var el = checkedItems.filter(function(el) {
    return el.Id === node.Id;
});

if (el.length) {
    el[0].IsChecked = node.checked;
} else {
   // push a new object
}

Answer 2

You can just use an object, which is guaranteed to have unique keys:

var checkedItems = {};
onItemChecked : function (e) {
    var node = e.sender.dataItem(e.node);
    checkedItems[node.Id] = node.checked;
},