How to get distinct values from an array of objects in JavaScript?

Question

Assuming I have the following:

var array = 
    [
        {\"name\":\"Joe\", \"age\":17}, 
        {\"name\":\"Bob\", \"age\":17}, 
        {\"name\":\"Carl\         


        

Answer 1

var unique = array
    .map(p => p.age)
    .filter((age, index, arr) => arr.indexOf(age) == index)
    .sort(); // sorting is optional

// or in ES6

var unique = [...new Set(array.map(p => p.age))];

// or with lodash

var unique = _.uniq(_.map(array, 'age'));

ES6 example

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

const arr = data.map(p => p.age); // [17, 17, 35]
const s = new Set(arr); // {17, 35} a set removes duplications, but it's still a set
const unique = [...s]; // [17, 35] Use the spread operator to transform a set into an Array
// or use Array.from to transform a set into an array
const unique2 = Array.from(s); // [17, 35]