if I have a js array like below, is there a simple way to re-group the array values by age? I tried to reduce it to an array but it did not help. it's re-grouped with age or name's
let employees = [
{
firstName:"Zion",
lastName: "Rosy",
age: 25,
joinedDate:"January 24, 2020",
},
{
firstName: "Ana",
lastName: "Rosy",
age: 25,
joinedDate: "January 15, 2019",
},
{
firstName: "Zion",
lastName:"Albert",
age: 30,
joinedDate:"February 15, 2011",
},
];
To re-group by age like this:
let organizedByAge =
{
25: [
{
firstName:"Zion",
lastName: "Rosy",
age: 25,
joinedDate:"January 24, 2020",
},
{
firstName: "Ana",
lastName: "Rosy",
age: 25,
joinedDate: "January 15, 2019",
},
],
30: [
{
firstName:"Zion",
lastName:"Albert",
age: 30,
joinedDate:"February 15, 2011",
},
],
};
is there a simple way to re-group the array values by age?
When rewriting arrays and objects, the most straightforward and readable approach is often to use a simple for loop:
for (let i = 0; i < employees.length; i++) {
const age = employees[i]['age'];
if (organizedByAge.hasOwnProperty(age)) {
organizedByAge[age].push(employees[i]);
}
else {
organizedByAge[age] = [];
organizedByAge[age][0] = employees[i];
}
}
Working Example:
let employees = [
{
firstName:"Zion",
lastName: "Rosy",
age: 25,
joinedDate:"January 24, 2020",
},
{
firstName: "Ana",
lastName: "Rosy",
age: 25,
joinedDate: "January 15, 2019",
},
{
firstName: "Zion",
lastName:"Albert",
age: 30,
joinedDate:"February 15, 2011",
},
];
let organizedByAge = {};
for (let i = 0; i < employees.length; i++) {
const age = employees[i]['age'];
if (organizedByAge.hasOwnProperty(age)) {
organizedByAge[age].push(employees[i]);
}
else {
organizedByAge[age] = [];
organizedByAge[age][0] = employees[i];
}
}
console.log(organizedByAge);Using Array#reduce:
const employees = [
{ firstName:"Zion", lastName: "Rosy", age: 25, joinedDate:"January 24, 2020" },
{ firstName: "Ana", lastName: "Rosy", age: 25, joinedDate: "January 15, 2019" },
{ firstName: "Zion", lastName:"Albert", age: 30, joinedDate:"February 15, 2011" }
];
const organizedByAge = employees.reduce((map, e) => ({
...map,
[e.age]: [...(map[e.age] ?? []), e]
}), {});
console.log(organizedByAge);const groupByKey = (_data, _key) => {
return _data.reduce((result, next) => {
const key = next[_key];
result[key] = result[key]?.length ? [...result[key], next] : [next];
return result;
}, {});
}
console.warn(groupByKey(employees, 'age'));