JS equivalent for jQuery one()

Update

In most browsers you can now pass in once: true in an options object:

document.getElementById('btn').addEventListener('click', () => {
  console.log('Hello and goodbye');
}, {
  once: true,
});
<button id="btn">Click me</button>

Old way

In the eventlistener callback, just destroy the event listener :) Here's a helper function:

function oneTimeEvent(element, eventType, callback) {
  element.addEventListener(eventType, function(e) {
    e.target.removeEventListener(e.type, arguments.callee);
    return callback(e);
  });
}

var btn = document.querySelector('button');
oneTimeEvent(btn, 'click', function () {
  alert('♫ You clicked me once, but I won\'t let you click me twice, yeah!');
});
<button>Click me!</button>

Here's a really simple solution using data attributes.

document.querySelector('#click').addEventListener('click', function(e){
    if(e.currentTarget.dataset.triggered) return;
    e.currentTarget.dataset.triggered = true;
    alert('clicked');
})
<button id="click">Click me</button>