getSelection = () => {
console.log("this", this); //valid but empty json
console.log("this.parentNode", this.parentNode); //<=undefined
}
document.querySelector('i.edit').addEventListener('click', getSelection, false);
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
<div class="control-group">
<label for="name" class="control-label">
<p class="text-info">Alex<i class="icon-star"></i> </p>
</label>
<input type="text" class="edit-input" />
<i class="fa fa-pencil edit" aria-hidden="true"></i>
</div>