Events¶

Events in Blessed work similar to the traditional node.js model, with one important difference: they have a concept of a tree and event bubbling.

Event Bubbling¶

Events can bubble in blessed. For example:

Receiving all click events for box (a normal event listener):

box.on('click', function(mouse) {
  box.setContent('You clicked ' + mouse.x + ', ' + mouse.y + '.');
  screen.render();
});

Receiving all click events for box, as well as all of its children:

box.on('element click', function(el, mouse) {
  box.setContent('You clicked '
    + el.type + ' at ' + mouse.x + ', ' + mouse.y + '.');
  screen.render();
  if (el === box) {
    return false; // Cancel propagation.
  }
});

el gets passed in as the first argument. It refers to the target element the event occurred on. Returning false will cancel propagation up the tree.