Need a way to get array of objects with mixed properties from an array of nested objects in JavaScript

Question

I have the following data that is an array of nested objects:

let sections = [
{
    name: "section1",
    id: 1,
    menus: [
      {
        id: 1,
        name: "menu1"
      },
      {
        id: 2,
        name: "menu2"
      }
      ]
  },
  {
    name: "section2",
    id: 2,
    menus: [
      {
        id: 3,
        name: "menu3"
      },
      {
        id: 4,
        name: "menu4"
      }
      ]
  }
]

I need an array of objects with properties from both nested objects. Expected Output:

[
{sectionId: 1, sectionName: "section1", menuId: 1, menuName: "menu1"},
{sectionId: 1, sectionName: "section1", menuId: 2, menuName: "menu2"},
{sectionId: 2, sectionName: "section2", menuId: 3, menuName: "menu3"},
{sectionId: 2, sectionName: "section2", menuId: 4, menuName: "menu4"}
]

Tried with below code:

let combined = sections.map(section => {
  let menus = section.menus.map(menu => {
    return{
      menuId: menu.id,
      menuName: menu.name,
      sectionName: section.name,
      sectionId: section.id
    }

  })  
  return menus
})

Actual Output:

[[{"menuId":1,"menuName":"menu1","sectionName":"section1","sectionId":1},{"menuId":2,"menuName":"menu2","sectionName":"section1","sectionId":1}],[{"menuId":3,"menuName":"menu3","sectionName":"section2","sectionId":2},{"menuId":4,"menuName":"menu4","sectionName":"section2","sectionId":2}]]

Getting Arrays of arrays of objects. Tried a lot using reduce and map but not getting the expected output. Any help is greatly appreciated.

Mamun · Accepted Answer · 2019-10-23 09:48:24Z

0

You can flat the returned result using Array.prototype.flat():

combined.flat()

let sections = [
{
    name: "section1",
    id: 1,
    menus: [
      {
        id: 1,
        name: "menu1"
      },
      {
        id: 2,
        name: "menu2"
      }
      ]
  },
  {
    name: "section2",
    id: 2,
    menus: [
      {
        id: 3,
        name: "menu3"
      },
      {
        id: 4,
        name: "menu4"
      }
      ]
  }
]



let combined = sections.map(section => {
  let menus = section.menus.map(menu => {
    return{
      menuId: menu.id,
      menuName: menu.name,
      sectionName: section.name,
      sectionId: section.id
    }

  })  
  return menus;
});
console.log(combined.flat());

answered Oct 23, 2019 at 9:48

Mamun

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1 Comment

Wamique Over a year ago

This is the easiest solution. Just added combined.flat() and it worked like a charm

Nina Scholz · Accepted Answer · 2019-10-23 09:48:41Z

0

You cold take Array#flatMap and map the inner array.

let sections = [{ name: "section1", id: 1, menus: [{ id: 1, name: "menu1" }, { id: 2, name: "menu2" }] }, { name: "section2", id: 2, menus: [{ id: 3, name: "menu3" }, { id: 4, name: "menu4" }] }],
    result = sections.flatMap(({ id: sectionId, name: sectionName, menus }) =>
        menus.map(({ id: menuId, name: menuName }) =>
            ({ sectionId, sectionName, menuId, menuName })
        )
    );

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

answered Oct 23, 2019 at 9:48

Nina Scholz

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Comments

Priya · Accepted Answer · 2019-10-23 09:55:45Z

0

Please try this with lodash. Look into Flatten an nested array of objects using Lodash you will definitely get answer

answered Oct 23, 2019 at 9:55

Priya

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