JSFiddle - React, Tailwind, and code Playground
HTML
<div id="halit">
</div>
JavaScript
var items = [{ad: "halit", yas: 10}, {ad:"ismet", yas: 15}, {ad:"halit", yas:13} ];
var filtered = items.filter( function( elm, idx, arr ) {
return arr.map( function( elmx, idxx ) {
return elm.ad == elmx.ad;
}).length > 0;
});
document.getElementById("halit").innerHTML = JSON.stringify(filtered);