Make an array of array from array of object

March 11, 2023

I just want to make an array from my data and list down each material base on the status.
My array show below..

let data = [
        {
            Name: 'House 1', 
            Details:[
                {Materials: 'Door', Status: 'Delivered'},
                {Materials: 'Closet', Status: 'Pending'},
                {Materials: 'Chair', Status: 'Pending'},
                {Materials: 'Kitchen', Status: 'Delivered'},
                {Materials: 'Door Knob', Status: 'Delivered'}
            ]
        },

        {
            Name: 'House 2', 
            Details:[
                {Materials: 'Cabinet', Status: 'Delivered'},
                {Materials: 'Kitchen', Status: 'Delivered'},
                {Materials: 'Door', Status: 'Ongoing'},
                {Materials: 'Chair', Status: 'Ongoing'},
                {Materials: 'Window', Status: 'Cancelled'}
            ]
        },
        //Other codes here...
    ];

I want to list down the status for each material.

Expected Output:

[
    0: 'House 1'
        [
            0: 'Delivered': [ 0: 'Door', 1: 'Kitchen', 2: 'Door Knob' ]
            1: 'Pending': [ 0: 'Closet, 1: 'Chair' ]
        ]
    1: 'House 2'
        [
            0: 'Cancelled': [ 0: 'Window' ]
            1: 'Delivered': [ 0: 'Cabinet', 1: 'Kitchen' ]
            2: 'Ongoing': [ 0: 'Chair', 1: 'Door' ]
        ]
]
//where 0:, 1:, 2: is the index of each array(*nested array)
//i just added index like what you see in console.log(*but it's not required to show in final output)

I’m trying to use forEach and .reduce but it seems my code doesn’t go well.

I hope you can resolve my problem 🙂

>Solution :

The structure you want cannot be represented solely by arrays; use objects instead for key-value pairs. You can use Array#reduce to group elements by their status into a single object.

let data=[{Name:"House 1",Details:[{Materials:"Door",Status:"Delivered"},{Materials:"Closet",Status:"Pending"},{Materials:"Chair",Status:"Pending"},{Materials:"Kitchen",Status:"Delivered"},{Materials:"Door Knob",Status:"Delivered"}]},{Name:"House 2",Details:[{Materials:"Cabinet",Status:"Delivered"},{Materials:"Kitchen",Status:"Delivered"},{Materials:"Door",Status:"Ongoing"},{Materials:"Chair",Status:"Ongoing"},{Materials:"Window",Status:"Cancelled"}]},];
let res = Object.fromEntries(data.map(o => [o.Name, o.Details.reduce((acc, curr) => {
  (acc[curr.Status] ??= []).push(curr.Materials);
  return acc;
}, {})]));
console.log(res);