var arr = [
{email: 'matthew@gmail.com', id: 10}
]
var arr2 = [
{email: 'matthew@gmail.com', id: 10},
{email: 'matthew@gmail.com', id: 13}
]
var mergedArray = arr.concat(arr2);
var map = new Map(mergedArray.map(o => [o.id,o]));
var unique = [...map.values()];
console.log(unique);