get unique values from array of objects javascript

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

                                    arr = [2, 2, 2, 1, 3, 3, 3,3, 4, 5];
arr = arr.sort().filter((item,i)=>!(arr[i] == arr[i+1] || arr[i-1]==arr[i]));
// this will remove all item which are repeating more then one
console.log(arr);
// [1, 4, 5]

                                    function toUniqueArray(a){<br/>    var newArr = [];<br/>    for (var i = 0; i &lt; a.length; i++) {<br/>        if (newArr.indexOf(a[i]) === -1) {<br/>            newArr.push(a[i]);<br/>        }<br/>    }<br/>  return newArr;<br/>}<br/>var colors = [&quot;red&quot;,&quot;red&quot;,&quot;green&quot;,&quot;green&quot;,&quot;green&quot;];<br/>var colorsUnique=toUniqueArray(colors); // [&quot;red&quot;,&quot;green&quot;]

                                    const data = [
  { group: 'A', name: 'SD' }, 
  { group: 'B', name: 'FI' }, 
  { group: 'A', name: 'MM' },
  { group: 'B', name: 'CO'}
];
const unique = [...new Set(data.map(item => item.group))]; // [ 'A', 'B']

                                    //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]