How to convert nested object array to single array dynamically

Question

// I have this kind of multiple object

_id: "5e5d00337c5e6a0444d00304"
    orderID: 10355
    orderDate: "2020-03-02"
    user:
       _id: "5e2e9699a648c53154f41025"
       name: "xyz1"
       email: "abcde@gmail.com"
       mNumber: 12336

// and I want this in a single array

orderID: 10354, 10355
orderDate:"2020-03-02","2020-03-02"
name: "xyz", "xyz1"
email: "abcd@gmail.com", "abcde@gmail.com"
mNumber: 1234536, 12336

My main objective is to get the excel sheet where under these headers id name email and so on i get those data. like

orderID    orderDate    name   email           mNumber
10354      2020-03-02   xyz   abcd@gmail.com   1234536
10355      2020-03-02   xyz1   abcde@gmail.com   12336

How should this be done in Angular?

Answer 1

If I understand you correctly, you can do something like this,

objs = [
  {
    _id: "5e5d00337c5e6a0444d00304",
    orderID: 10354,
    orderDate: "2020-03-02",
    user:
    {
      _id: "5e2e9699a648c53154f41025",
      name: "xyz",
      email: "abcd@gmail.com",
      mNumber: 1234536
    }
  },
  {
    _id: "5e5d00337c5e6a0444d00304",
    orderID: 10355,
    orderDate: "2020-03-02",
    user:
    {
      _id: "5e2e9699a648c53154f41025",
      name: "xyz1",
      email: "abcde@gmail.com",
      mNumber: 12336
    }
  }
];
const arr = [];
for (const o of objs) {
  arr.push([
    o.orderID,
    o.orderDate,
    o.user.name,
    o.user.email,
    o.user.mNumber
  ]);
}
console.log(arr);

This is the output,

[ [ 10354, '2020-03-02', 'xyz', 'abcd@gmail.com', 1234536 ],
  [ 10355, '2020-03-02', 'xyz1', 'abcde@gmail.com', 12336 ] ]

Basically it is just an iteration.

I am going to add another solution. In this case, you don't want to describe all the values that goes in the row, but instead you want to describe the values you don't want in the row. You can use a recursive function to traverse the objects in this situation. fields is the object where you describe wich values goes and witch don't. Something like this.

const fields = { _id: false, user: { _id: false} }
function toRowRec(obj, fields) {
  let row = [];
  const keys = Object.keys(obj);
  for (const k of keys) {
    if (!fields.hasOwnProperty(k)) {
      row.push(obj[k]);
    } else if (typeof obj[k] === 'object' && obj[k] !== null) {
      row = row.concat(toRowRec(obj[k], fields[k])); 
    }
  }
  return row;
}
let arr = []
for (const o of objs) {
  arr.push(toRowRec(o, fields));
}
console.log(arr);

I omit the input objs (same as previous), and you will get the exact output than before.

You will see that I am also omitting the keys that I want to put in the row, to do this I am just checking if the key is in the fields object.