Vanilla implementation of jQuery .on() method

on.js

/**
 * Delegation capable of detecting multiple events at the same time
 * @param {string} events - space separated list of events
 * @param {string} selector - CSS selector string
 * @param {function} handler - callback function to call when event is captured
 * @return {Object} - this object, for chaining
 * @example
 * containerElement.on("input", "input[type=tel]", function () {
 *   this.value = this.value.replace(/\D/g, "");
 * });
 */
function on(events, selector, handler) {
  events.split(' ').forEach(e => {
    this.addEventListener(e, function(e) {
      const t = e.target;
      while (t && t !== this) {
        t.matches(selector) && handler.call(t, e);
        t = t.parentNode;
      }
    });
  });
  return this;
}