Asynchronous context items

Instead of an array, you can use a function that invokes a callback. When you invoke the callback you pass an array to it to add items to the context menu asynchronously.

import canvasDatagrid from 'canvas-datagrid';
import data from '/data.json';

const app = document.getElementById('app');
const gridElement = document.createElement('div');
const grid = canvasDatagrid({
  parentNode: gridElement,
  data,
});

grid.addEventListener('contextmenu', function (e) {
  e.items.push({
    title: 'Asynchronous child context menu item',
    items: function (callback) {
      setTimeout(function () {
        callback([
          {
            title: 'I was added later',
            click: function () {
              return;
            },
          },
        ]);
      }, 500);
    },
  });
});

app.append(gridElement);