const res = [...a, ...b, ...c] // склеили
const logicalFunction = (acc, item)=>{
if(acc[item.id]){
// попытка мержа , merge напиши сам
acc[item.id] = merge(acc[item.id], item);
} else {
acc[item.id] = item;
}
return acc;
}
const obj = res.reduce(logicalFunction, {});
const final = Object.values(obj).sort((a,b)=b.id-a.id)