Object Compare

compare.js

var accountUsers = [
  {_id:1, email:'email1'},
  {_id:2, email:'email2'},
  {_id:3, email:'email3'},
  {_id:4, email:'email4'},
  {_id:5, email:'email5'},
];

var calendarUsers = [
  {_id:1, email:'email1', status: 'pending'},
  {_id:2, email:'email2', status: 'active'},
  {_id:3, email:'email3', status: null},
];

// get eligible users for calendar user list

function comparer(arr){
  return function(cur) {
    return arr.filter(a => a.email === cur.email).length == 0; 
  }
}

var eligibleList = accountUsers.filter(comparer(calendarUsers));

console.log(eligibleList);

/*
[
  {
    "_id": 4,
    "email": "email4"
  },
  {
    "_id": 5,
    "email": "email5"
  }
]
*/