Extract elements from the nested object's virtuals and add them to the main object array

Question

Extract elements from the nested object's virtuals and add them to the main object array

I have an array of objects with nested arrays, all with a similar structure. I want to flatten the array so that all objects are on the same level.

[
  {
   "name": "United States",
   "slug": "united-states",
   "states":[
     {
      "name": "Arizona",
      "slug": "arizona"
     },
     {
      "name": "California",
      "slug": "california"
     }
    ]
  },
  {
   "name": "Canada",
   "slug": "canada",
  }

]

The resulting flattened array should look like this:

[
  {
   "name": "United States",
   "slug": "united-states"
  },
  {
   "name": "Arizona",
   "slug": "arizona"
  },
  {
   "name": "California",
   "slug": "california"
  },
  {
   "name": "Canada",
   "slug": "canada",
  }

]

javascript arrays json javascript-objects

Answer 1

Answer №1

By leveraging the power of Array#flatMap:

const data = [
  {
    "name": "United States",
    "slug": "united-states",
    "states":[
      { "name": "Arizona", "slug": "arizona" },
      { "name": "California", "slug": "california" }
    ]
  },
  { "name": "Canada", "slug": "canada" }
];

const res = data.flatMap(({ name, slug, states = [] }) => ([
  { name, slug },
  ...states
]));

console.log(res);

Answer 2

By leveraging the power of Array#flatMap:

const data = [
  {
    "name": "United States",
    "slug": "united-states",
    "states":[
      { "name": "Arizona", "slug": "arizona" },
      { "name": "California", "slug": "california" }
    ]
  },
  { "name": "Canada", "slug": "canada" }
];

const res = data.flatMap(({ name, slug, states = [] }) => ([
  { name, slug },
  ...states
]));

console.log(res);

Answer 3

Answer №2

If you want to efficiently navigate through a tree structure, one approach is to create an iterator specifically for that purpose and then convert it into an array. This method is effective even for deeply nested trees and doesn't require knowledge of which property holds the child nodes. It assumes that the property containing an Array value represents the subtrees:

function * traverse(forest) {
    for (const item of forest) {
        const arrayKey = Object.entries(item).find(([k, v]) => Array.isArray(v))?.[0];
        const { [arrayKey]: children, ...rest } = item;
        yield rest;
        if (children) yield * traverse(children);
    }
}

const data = [{"name": "United States","slug": "united-states","states":[{ "name": "Arizona", "slug": "arizona" },{ "name": "California", "slug": "california" }]},{ "name": "Canada", "slug": "canada" }];

const res = [...traverse(data)];

console.log(res);

Answer 4

If you want to efficiently navigate through a tree structure, one approach is to create an iterator specifically for that purpose and then convert it into an array. This method is effective even for deeply nested trees and doesn't require knowledge of which property holds the child nodes. It assumes that the property containing an Array value represents the subtrees:

function * traverse(forest) {
    for (const item of forest) {
        const arrayKey = Object.entries(item).find(([k, v]) => Array.isArray(v))?.[0];
        const { [arrayKey]: children, ...rest } = item;
        yield rest;
        if (children) yield * traverse(children);
    }
}

const data = [{"name": "United States","slug": "united-states","states":[{ "name": "Arizona", "slug": "arizona" },{ "name": "California", "slug": "california" }]},{ "name": "Canada", "slug": "canada" }];

const res = [...traverse(data)];

console.log(res);

Extract elements from the nested object's virtuals and add them to the main object array

Answer №1

Answer №2

Similar questions

Issue with showing second page in form post using Express.js: node.js, express.js and jade

Mongoose Error: Incompatible receiver called Method Uint8Array.length

Multiple individual image uploads via ajax on a single webpage

Delete any classes that start with a specific prefix

When the page is refreshed, the JWT token mysteriously disappears from the header. How can this issue be resolved

Using JavaScript to parse JSON data containing additional curly braces

The method is called after the focus is removed from the element

"An error occurred with the Ajax post request - bad request

JavaScript allows you to create matrices from squares

" Jquery.ajax, PHP, and the case of the mysteriously missing response

Tips for preventing multiple links from opening when clicking the same link

Refreshing the DeckGL HexagonLayer upon changes to the data array/Initiating a reload for the DeckGL HexagonLayer

Incorporate a delay when using jQuery's mouseenter function

The $(document).ready function may not be compatible with Internet Explorer

Utilizing @casl/vue in conjunction with pinia: A guide to integrating these

Updating AngularJS views based on window resizing

The Vuetify navigation drawer seems to have a quirk where it only closes after an item

The dynamic duo of web development: React and Bootstrap JavaScript

When using `element.addEventListener`, event.target will be the target

Retrieving a single value from the response entity JSON data