I have an array of objects like this :
const arr = [
{"id" : 1, "name" : "john", "age": 12, "fruits": "banana"},
{"id" : 2, "name" : "john", "age": 12, "fruits": "apple"}
{"id" : 3, "name" : "maria", "age": 13, "fruits": "grappes"}
{"id" : 4, "name" : "maria", "age": 13, "fruits": "blackberry"}
{"id" : 5, "name" : "camille", "age": 12, "fruits": "cherry"}
]
I would like to have a single object for each person (name) and add their objects.
So the final array would be :
const arr = [
{"id" : 1, "name" : "john", "age": 12, "fruits": ["banana", "apple"]},
{"id" : 3, "name" : "maria", "age": 13, "fruits": ["grappes", "blackberry"]}
{"id" : 5, "name" : "camille", "age": 12, "fruits": ["cherry"]}
];
The real array I am using is very big this is why I am looking for the most efficient way of doing this.
You can use Array.prototype.reduce to group the objects.
const arr = [
{ id: 1, name: "john", age: 12, fruits: "banana" },
{ id: 2, name: "john", age: 12, fruits: "apple" },
{ id: 3, name: "maria", age: 13, fruits: "grappes" },
{ id: 4, name: "maria", age: 13, fruits: "blackberry" },
{ id: 5, name: "camille", age: 12, fruits: "cherry" },
];
const output = Object.values(
arr.reduce((res, o) => {
if (!res[o.name]) {
res[o.name] = { ...o, fruits: [] };
}
res[o.name].fruits.push(o.fruits);
return res;
}, {})
);
console.log(output);You can also write the above solution more succinctly:
const arr = [
{ id: 1, name: "john", age: 12, fruits: "banana" },
{ id: 2, name: "john", age: 12, fruits: "apple" },
{ id: 3, name: "maria", age: 13, fruits: "grappes" },
{ id: 4, name: "maria", age: 13, fruits: "blackberry" },
{ id: 5, name: "camille", age: 12, fruits: "cherry" },
];
const output = Object.values(
arr.reduce(
(res, o) => ((res[o.name] ||= { ...o, fruits: [] }).fruits.push(o.fruits), res),
{}
)
);
console.log(output);