groupby javascript by instances
let people = [ { name: 'Alice', age: 21 }, { name: 'Max', age: 20 }, { name: 'Jane', age: 20 } ]; function groupBy(objectArray, property) { return objectArray.reduce(function (acc, obj) { let key = obj[property] if (!acc[key]) { acc[key] = [] } acc[key].push(obj) return acc }, {}) } let groupedPeople = groupBy(people, 'age') // groupedPeople is: // { // 20: [ // { name: 'Max', age: 20 }, // { name: 'Jane', age: 20 } // ], // 21: [{ name: 'Alice', age: 21 }] // }