visjs timeline - set initial vertical position of items

Question

I'm using vis-timeline to render a hundred rows of data. When the component loads, I want to see the rows starting from the beginning: 1, 2, 3, and so on. Instead, by default, vis-timeline starts by displaying the end of the list (...97, 98, 99, 100), so that you have to scroll up to get to the top?

There are methods like setWindow() for setting the horizontal time frame, but what about the vertical position? I've tried the HTML scroll() method, but that doesn't seem to do anything.

Normally I would use orientation: { item: 'top' } } in the options, but there is a bug that prevents scrolling in that case; it must be set to 'bottom'.

I've thought about initializing the component with the orientation to 'top', then once it displays, setting it to 'bottom' to allow scrolling, but that seems pretty hacky.

Is there a cleaner solution?

user_765395 · Answer

You can implement a custom ordering function for items (groups as well) using the order configuration option:

Provide a custom sort function to order the items. The order of the items is determining the way they are stacked. The function order is called with two arguments containing the data of two items to be compared.

WARNING: Use with caution. Custom ordering is not suitable for large amounts of items. On load, the Timeline will render all items once to determine their width and height. Keep the number of items in this configuration limited to a maximum of a few hundred items.

See below for an example:

var items = new vis.DataSet();
for (let i=0; i<100; i++) {
  items.add({
    id: i,
    content: 'item ' + i,
    start: new Date(2022, 4, 1),
    end: new Date(2022, 4, 14)
  });
}

var container = document.getElementById('visualization1');
var options = {
  order: function (a, b) {
      return b.id - a.id;
    }
}
var timeline = new vis.Timeline(container);
timeline.setOptions(options);
timeline.setItems(items);

visjs timeline - set initial vertical position of items

1 Answers