Determine the difference between values in object and array

Question

I have the following object and array of numbers. How can I tell which number in the array does not exist as an id in the object? In the following example, I would want 1453.

[
  {id: 60, itemName: 'Main Location - 1100 Superior Road - Cleveland'}
  {id: 1456, itemName: 'Third Location - 107,West 20th Street,Manhattan - New York'}
]

[60, 1453, 1456]

Answer 1

You could create an IDs list of the existing data IDs using .map(), and then use .filter() and .includes()

const data = [
  {id: 60, itemName: 'Main Location - 1100 Superior Road - Cleveland'},
  {id: 1456, itemName: 'Third Location - 107,West 20th Street,Manhattan - New York'}
]

const ids = [60, 1453, 1456];
const dataIDs = data.map(ob => ob.id);  // [60, 1456]
const notExistentIDs = ids.filter(id => !dataIDs.includes(id));

console.log(notExistentIDs);  // [1453]

which will return an Array of all the Object IDs (from data) not listed in your reference ids Array.