Node with id=0 cannot be deleted

[FilipQL]

Hi,

I have a very simple app created with Vis and the problem is that the node with id=0 cannot be deleted. All of the other nodes can be deleted.

Here is the example: https://jsfiddle.net/Filip_Z/9k2s3dgj/7/

    // create an array with nodes
    var nodes = new vis.DataSet([
        { id: 0, label: '0' },
        { id: 1, label: '1' },
        { id: 2, label: '2' },
        { id: 3, label: '3' },
        { id: 4, label: '4' }
    ]);

    // create an array with edges
    var edges = [];

    // create a network
    var container = document.getElementById('mynetwork');

    // provide the data in the vis format:
    var data = {
        nodes: nodes,
        edges: edges
    };

    var options = {
        manipulation: {
            enabled: true,
            initiallyActive: true,
            deleteNode: function(deleteData, callback) {
                callback(deleteData)
            }
        }
    };

    // initialize your network!
    var network = new vis.Network(container, data, options);

As @danieldiekmeier suggested, this is most likely because Vis checks for truthy-ness in the ids (because if you use a string as the id, it works, and you can remove the node):

nodes: [
    { id: '0', label: '0' },
    { id: 1, label: '1' },
    { id: 2, label: '2' },
    { id: 3, label: '3' },
    { id: 4, label: '4' }
]

[lewisjb]

This appears to actually be a problem with DataSet. I noticed the same problem in some of the Timeline examples (Ordering of groups and Subgroups)

I did some debugging, and found that it is because of a 'truthy-ness' check.
The issue is here: DataSet.js:682
Lines:

itemId = item[this._fieldId];
if (itemId) {
  removedIds.push(itemId);
  removedItems.push(item);
}

I did a manual override in debug mode, to run those two lines for when id is 0, and it worked.

It appears the original purpose of the if was to ensure that itemId existed, in which case changing it to: if (itemId != undefined) should resolve the issue without any side-effects.

[yotamberk]

fixed with #2530