[Aetae]

function uniqSelected(...args){
  const out = [];
  const map = {};
    
  args.forEach(arr => arr.forEach(item => {
    const {id} = item;
    if(id in map) 
      return map[id].selected = true;
    out.push(map[id] = {...item});
  }));
  
  return out;
}