Get missing objects from 2 arrays of objects

Question

let selected = [
  {id: 15, name: 'Canada'},
  {id: 25, name: 'Germany'}
];

let all = [
  {id: 15, name: 'Canada'},
  {id: 25, name: 'Germany'},
  {id: 32, name: 'United States'},
  {id: 40, name: 'China'}
]

How do I get non-selected countries from all objects and print it out in another variable? Based on id key of those which are in selected array?

Answer 1

You need to find all objects that aren't contained in selected and then do something with them:

let nonSelectedItems = all.filter(obj => selected.every(s => s.id !== obj.id));

//do stuff with non-selected items