Preventing event bubbling in JS

index.js

var el = document.createElement("div");
document.body.innerHTML = "";
document.body.appendChild(el);

document.body.addEventListener("foobar", announce);
el.addEventListener("foobar", preventBubble(announce));

var event = new CustomEvent("foobar", { bubbles: true, detail: "Hello" });
el.dispatchEvent(event); // "ANNOUNCING: Hello"

function announce(ev) {
  console.log("ANNOUNCING: " + ev.detail);
}

preventBubble.js

function preventBubble(arg) {
  if (arg instanceof Event) {
    return _handleEvent(arg);
  }

  if (typeof arg === "function") {
    return _handleFunction(arg);
  }

  throw new TypeError("Argument must be an Event or a callback");
}

function _handleEvent(ev) {
  if (ev.stopPropogation) {
    ev.stopPropogation();
  } else {
    ev.cancelBubble = true;
  }

  return ev;
}

function _handleFunction(callback) {
  return function(ev) {
    _handleEvent(ev);
    return callback(ev);
  };
}