Exclude array items from another

exclusiveArrayFiltering.js

const allClasses = [
  {
    id: 1,
    name: 'Yoga 100',
    enrolled: 10,
    maxCapacity: 11,
  },
  {
    id: 2,
    name: 'Yoga 200',
    enrolled: 11,
    maxCapacity: 11,
  },
  {
    id: 3,
    name: 'Yoga 300',
    enrolled: 8,
    maxCapacity: 11,
  },
  {
    id: 4,
    name: 'Yoga 400',
    enrolled: 1,
    maxCapacity: 11,
  },
  {
    id: 5,
    name: 'Yoga 500',
    enrolled: 10,
    maxCapacity: 11,
  },
];

const userEnrolledClasses = [
  {
    id: 34,
    name: 'Yoga 300',
    classId: 3,
  },
  {
    id: 58,
    name: 'Yoga 500',
    classId: 5,
  },
];

// Get just the id's of the classes the user is enrolled in
const userEnrolledClassIds = userEnrolledClasses.map(cls => cls.classId);

// Filter out all classes that the user is already enrolled in
const availableClasses = allClasses.filter(cls => !userEnrolledClassIds.includes(cls.id))

// This will print all classes the user is not enrolled in
console.log(availableClasses);