show duplocates in array javascrpt code example

Example 1: remove duplicates from array javascript

arr.filter((v,i,a)=>a.findIndex(t=>(t.place === v.place && t.name===v.name))===i)

Example 2: use set to remove duplicates in javascript

const names = ['John', 'Paul', 'George', 'Ringo', 'John'];

function removeDups(names) {
  let unique = {};
  names.forEach(function(i) {
    if(!unique[i]) {
      unique[i] = true;
    }
  });
  return Object.keys(unique);
}

removeDups(names); // // 'John', 'Paul', 'George', 'Ringo'