getElementAtEvent(e) - Javascript

In Javascript, getElementAtEvent(e) is a function that is commonly used in libraries like Chart.js or Plotly.js to get the element at a specific point on the canvas.

This function returns an array of elements that intersect with the point represented by the event e object. The elements are ordered by their distance from the pointer position, with the closest one being first.

Here's an example usage of getElementAtEvent(e):

canvas.addEventListener('click', function(e) {
  var activeElements = chart.getElementAtEvent(e);
  if (activeElements.length > 0) {
    // Do something with the clicked element(s)
  }
});

The above code adds a click event listener to a canvas and uses getElementAtEvent(e) to get the clicked element(s) if any.

It's important to note that getElementAtEvent(e) may not work for all types of charts or elements. For example, it may not work for elements that are not drawn on a canvas or elements that have no interactivity enabled.

Overall, getElementAtEvent(e) is a useful function for getting information about elements that are interacted with on a canvas, and is a commonly used function in various Javascript visualization libraries.