e.target

// HTML
<div id="first" class="content"></div>
<div id="second" class="content"></div>

//JS
var first = document.querySelector("#first");
var second = document.querySelector("#second");

var clickedLink = {
  first: 0,
  second: 0
}

var click = function(e) {
  // switch - case
  if(e.target.id === "first") { 
    clickedLink.first++;
  }
  if(e.target.id === "second") { 
    clickedLink.second++;
  }
  console.log(clickedLink);
}

// querySelectorAll
first.addEventListener('click', click);
second.addEventListener('click', click);