Flatten an object that is nested inside an array

Question

Flatten an object that is nested inside an array

I want to take the value of the first key:value pair and apply it to each value in the array of the second key:value pair, all while removing the keys from the books array. This process will result in a list that looks like this:

var fictionCatalog = [
  {
    author: 'Michael Crichton',// push into each book
    books: [
      {name: 'Sphere', price: 10.99},
      {name: 'Jurassic Park', price: 5.99},
      {name: 'The Andromeda Strain', price: 9.99},
      {name: 'Prey', price: 5.99}
    ]
  }
]

The desired output should be:

[
 [ Michael Crichton, 'Sphere', 10.99 ], 
 [ Michael Crichton, 'Jurassic Park', 5.99 ],
 [ Michael Crichton, 'The Andromeda Strain', 9.99 ],
 [ Michael Crichton, 'Prey', 5.99 ]
]

However, I am facing difficulties with the following code snippet:

var fictionCatalog = [
  {
    author: 'Michael Crichton',
    books: [
      {name: 'Sphere', price: 10.99},
      {name: 'Jurassic Park', price: 5.99},
      {name: 'The Andromeda Strain', price: 9.99},
      {name: 'Prey', price: 5.99}
    ]
  }
]

var collection = fictionCatalog.reduce(function(prev, curr) {
  return prev.concat(curr.author, curr.books);
}, []);

console.log(collection)

javascript arrays flatten

Answer 1

Answer №1

To transform the data from the books array, you can use a mapping function like so:

var collection = fictionCatalog.map(function(obj) {
  return obj.books.map(function(book) {
    return [obj.author, book.name, book.price];
  });
});

console.log(collection);

Result:

[ [ [ 'Michael Crichton', 'Sphere', 10.99 ],
    [ 'Michael Crichton', 'Jurassic Park', 5.99 ],
    [ 'Michael Crichton', 'The Andromeda Strain', 9.99 ],
    [ 'Michael Crichton', 'Prey', 5.99 ] ] ]

For each entry in the fictionCatalog, we apply a mapping function and gather the output in an array. This function then further applies another function to each book within the entry, returning an array containing the author's name, book title, and price.

Answer 2

To transform the data from the books array, you can use a mapping function like so:

var collection = fictionCatalog.map(function(obj) {
  return obj.books.map(function(book) {
    return [obj.author, book.name, book.price];
  });
});

console.log(collection);

Result:

[ [ [ 'Michael Crichton', 'Sphere', 10.99 ],
    [ 'Michael Crichton', 'Jurassic Park', 5.99 ],
    [ 'Michael Crichton', 'The Andromeda Strain', 9.99 ],
    [ 'Michael Crichton', 'Prey', 5.99 ] ] ]

For each entry in the fictionCatalog, we apply a mapping function and gather the output in an array. This function then further applies another function to each book within the entry, returning an array containing the author's name, book title, and price.

Answer 3

Answer №2

Using a combination of map functions can help solve the problem

var fictionCatalog = [
  {
    author: 'Michael Crichton',// push into each book
    books: [
      {name: 'Sphere', price: 10.99},
      {name: 'Jurassic Park', price: 5.99},
      {name: 'The Andromeda Strain', price: 9.99},
      {name: 'Prey', price: 5.99}
    ]
  }
];

var res = fictionCatalog.map(v => {
  return v.books.map(k => {
  return [v.author, k.name, k.price];
  })
});

console.log(res);

Answer 4

Using a combination of map functions can help solve the problem

var fictionCatalog = [
  {
    author: 'Michael Crichton',// push into each book
    books: [
      {name: 'Sphere', price: 10.99},
      {name: 'Jurassic Park', price: 5.99},
      {name: 'The Andromeda Strain', price: 9.99},
      {name: 'Prey', price: 5.99}
    ]
  }
];

var res = fictionCatalog.map(v => {
  return v.books.map(k => {
  return [v.author, k.name, k.price];
  })
});

console.log(res);

Answer 5

Answer №3

If I were to solve this, I would use a simple loop:

var fictionCatalog = [
  {
    author: 'Michael Crichton',
    books: [
      {name: 'Sphere', price: 10.99},
      {name: 'Jurassic Park', price: 5.99},
      {name: 'The Andromeda Strain', price: 9.99},
      {name: 'Prey', price: 5.99}
    ]
  }
]

var collection = [];

for (var a = 0; a < fictionCatalog.length; a++) {
  var author = fictionCatalog[a].author;
  for (var b = 0; b < fictionCatalog[a].books.length; b++) {
     collection.push([
         author,
         fictionCatalog[a].books[b].name,
         fictionCatalog[a].books[b].price
     ]);
  }
}

console.log(collection)

Answer 6

If I were to solve this, I would use a simple loop:

var fictionCatalog = [
  {
    author: 'Michael Crichton',
    books: [
      {name: 'Sphere', price: 10.99},
      {name: 'Jurassic Park', price: 5.99},
      {name: 'The Andromeda Strain', price: 9.99},
      {name: 'Prey', price: 5.99}
    ]
  }
]

var collection = [];

for (var a = 0; a < fictionCatalog.length; a++) {
  var author = fictionCatalog[a].author;
  for (var b = 0; b < fictionCatalog[a].books.length; b++) {
     collection.push([
         author,
         fictionCatalog[a].books[b].name,
         fictionCatalog[a].books[b].price
     ]);
  }
}

console.log(collection)

Answer 7

Answer №4

What do you think of this approach:

let fictionAuthors = [
 {
   name: 'Michael Crichton',
   novels: [
      {title: 'Sphere', cost: 10.99},
      {title: 'Jurassic Park', cost: 5.99},
      {title: 'The Andromeda Strain', cost: 9.99},
      {title: 'Prey', cost: 5.99}
    ]
  }
]

let bookList = fictionAuthors.reduce(
  function(previous, current) {  
    return previous.concat( current.novels.map( 
                               function(item) { 
                                 return [ current.name, item.title, item.cost ]; 
                               }));
}, []);

This method utilizes the reduce and map functions to create the desired array structure.

Answer 8

What do you think of this approach:

let fictionAuthors = [
 {
   name: 'Michael Crichton',
   novels: [
      {title: 'Sphere', cost: 10.99},
      {title: 'Jurassic Park', cost: 5.99},
      {title: 'The Andromeda Strain', cost: 9.99},
      {title: 'Prey', cost: 5.99}
    ]
  }
]

let bookList = fictionAuthors.reduce(
  function(previous, current) {  
    return previous.concat( current.novels.map( 
                               function(item) { 
                                 return [ current.name, item.title, item.cost ]; 
                               }));
}, []);

This method utilizes the reduce and map functions to create the desired array structure.

Flatten an object that is nested inside an array

Answer №1

Answer №2

Answer №3

Answer №4

Similar questions

You cannot cast java.lang.Double to abie47_0_0.com.facebook.react.bridge.ReadableMap in this scenario

Patience is key when using Selenium with Node.js - make sure to wait for the

Using jQuery to enhance the functionality of the drop-down select feature

Set up global variables for components to access

What is the best way to modify navbar-default to navbar-inverse when scrolling?

What is the best way to highlight the option with a value of 0 by giving it a red background using either CSS, jQuery, or both, regardless of whether it is

Issues encountered with Jquery hover functionality not responding as expected

Error: the function was not defined and has not been caught

Generating random strings does not modify my string array in C++

Implementing re-render logic for a React functional component based on changes in useState()

Why is the ExpressJS response for a POST request returning as undefined upon connecting to MongoDB?

Error alert: Unable to find the specified word

Troubles with NextJS and TailwindCSS Styling

Filter Observable based on object array property

Create a 3D visual display with the use of three.js in Javascript

Netlify encountered an error with mixed content, indicating that the page was successfully loaded over HTTPS, but it attempted to request an insecure HTTP

Issue with Ajax: parameters failing to pass without using jQuery

"Add a hover effect to fade the image and make it clickable for a

Creating a struct in C that contains a multidimensional, dynamic array where the size is determined by an integer defined within the same struct

Connect the mileage tracker to a Datalist or grid view component