//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]
const categories = ['General', 'Exotic', 'Extreme', 'Extreme', 'General' ,'Water', 'Extreme'] .filter((value, index, categoryArray) => categoryArray.indexOf(value) === index); This will return an array that has the unique category names ['General', 'Exotic', 'Extreme', 'Water']
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']