javascript unique array of objects by property

                                    const unique = [...new Set(array.map(item => item.age))];

                                    const array = [    { id: 3, name: 'Central Microscopy', fiscalYear: 2018 },    { id: 5, name: 'Crystallography Facility', fiscalYear: 2018 },    { id: 3, name: 'Central Microscopy', fiscalYear: 2017 },    { id: 5, name: 'Crystallography Facility', fiscalYear: 2017 }  ];const result = [];const map = new Map();for (const item of array) {    if(!map.has(item.id)){        map.set(item.id, true);    // set any value to Map        result.push({            id: item.id,            name: item.name        });    }}console.log(result)

                                    //ES6
let array = [
  { "name": "Joe", "age": 17 },
  { "name": "Bob", "age": 17 },
  { "name": "Carl", "age": 35 }
];
array.map(item => item.age)
  .filter((value, index, self) => self.indexOf(value) === index)

> [17, 35]

                                    var flags = [], output = [], l = array.length, i;
for( i=0; i<l; i++) {
    if( flags[array[i].age]) continue;
    flags[array[i].age] = true;
    output.push(array[i].age);
}

                                    const array =
  [
    { "name": "Joe", "age": 17 },
    { "name": "Bob", "age": 17 },
    { "name": "Carl", "age": 35 }
  ]

function uniqueByKey(array, key) {
  return [...new Map(array.map((x) => [x[key], x])).values()];
}

console.log(uniqueByKey(array, 'age'));