jquery - Adding an event listener to an element that doesn't exist yet in vanilla javascript -

in jquery can do:

$(document).on("click","a.somebtn",function(e){     console.log("hi"); }); 

to add event listener element doesn't exist yet. cannot seem figure out how add event listener element not exist yet in vanilla javascript.
following not work obviously:

query.addeventlistener( "click", somelistener ); 

edit

what compare item query selectors. selecting element not exist yet queryselectorall. little more dynamic checking tag name.

use target property in event object clicked element. then, manually test type/attributes/ids

document.addeventlistener( "click", somelistener );  function somelistener(event){     var element = event.target;     if(element.tagname == 'a' && element.classlist.contains("somebtn")){         console.log("hi");     } }