Should DataGroup model include the treeLevel parameter?

[clasit]

Prerequisites

ngx-vis (3.1.0) to include the vis-timeline (7.4.2) into an Angular (10.1.2) project.

Current Behavior

I'm using the DataGroup (imported from 'ngx-vis') model to define groups and subgroups, for example:

const groups: DataGroup[] = [{
    id: 1,
    content: 'Parent',
    nestedGroups: [2, 3]
}, {
    id: 2,
    content: 'Child 1'
}, {
    id: 3,
    content: 'Child 2'
}];

Expected Behavior

The model DataGroup should include the treeLevel parameter, which is needed by vis-timeline to render the subgroups properly:

const groups: DataGroup[] = [{
    id: 1,
    content: 'Parent',
    nestedGroups: [2, 3],
    treeLevel: 1
}, {
    id: 2,
    content: 'Child 1',
    treeLevel: 2
}, {
    id: 3,
    content: 'Child 2',
    treeLevel: 2
}];

I don't understand why this parameter lacks in the DataGroup model.

I checked the vis-timeline Documentation for groups, but the treeLevel is not explained.
https://visjs.github.io/vis-timeline/docs/timeline/#groups

[marcortw]

Hi @clasit, I just had the same question and it seems like this is now the case. The example from https://github.com/visjs/vis-timeline/blob/master/examples/timeline/groups/nestedThreeLevels.html uses the treeLevel key, and it's not assigned anywhere else. It looks like if we don't supply it, it by default now renders it with an ugly red box around it. Would be nice if that would be explained somewhere, it feels like a breaking change.