I'm trying to figure out how to extract result based on an object property value that is inside another object e.g

{
   title: 'The Book',
   author: {
      name: 'Merlin Bridge',
      category: 'Fiction'
   }
}  

Here are my tests:

  // this works
  const test1 = _.find(existingBooks, {
    title: uploadedBooks[i].title,
  });

  // this doesn't work and returns nothing
  const test2 = _.find(existingBooks, {
    'author.name': uploadedBooks[i].author.name,
  });

I want to get the result wherein the author.name is the identifier. Thanks a lot.

I'm trying to figure out how to extract result based on an object property value that is inside another object e.g

{
   title: 'The Book',
   author: {
      name: 'Merlin Bridge',
      category: 'Fiction'
   }
}  

Here are my tests:

  // this works
  const test1 = _.find(existingBooks, {
    title: uploadedBooks[i].title,
  });

  // this doesn't work and returns nothing
  const test2 = _.find(existingBooks, {
    'author.name': uploadedBooks[i].author.name,
  });

I want to get the result wherein the author.name is the identifier. Thanks a lot.

• javascript
• lodash

5 Answers 5

As you are using Lodash/Underscore find, I took the liberty to also use the get helper. Please find below an answer which should help you.

const books = [{
    title: 'The Book',
    author: {
      name: 'Merlin Bridge',
      category: 'Fiction'
    }
  },
  {
    title: 'Another Book',
    author: {
      name: 'Merlin Window',
      category: 'Science'
    }
  }
];
const uploadedBooks = [{
    title: 'Another Book',
    author: {
      name: 'Merlin Window',
      category: 'Science'
    }
  }];
const i = 0;
const foundBook = _.find(books, (book, index) => {
  return _.get(book, 'author.name') === _.get(uploadedBooks, [i, 'author', 'name'])
});
console.log(foundBook);

<script src="https://cdn.jsdelivr/npm/[email protected]/lodash.min.js"></script>

You can Use below code to iterate your json object.

var myObj = {
   title: 'The Book',
   author: {
      name: 'Merlin Bridge',
      category: 'Fiction'
   }
} 
Object.keys(myObj).forEach(key => {
    console.log(JSON.stringify(myObj[key]));
  });

It's possible to add dynamically named properties to JavaScript objects.

Assuming you are looping an array and not an object:

var a = _.map(existingBooksArray, function(existingBook) {
    return {[existingBook.author.name]: existingBook.title}
});

Result of a:

[
    {
        Merlin Bridge: "The Book"
    }
]

use .key method

Object.keys(myObj).forEach(key => {
console.log(myObj[key]);});

var myObj = {
   title: 'The Book',
   author: {
      name: 'Merlin Bridge',
      category: 'Fiction'
   }
} 

Object.keys(myObj).forEach(key => {
    console.log(JSON.stringify(myObj[key]));
  });

var myObj = {
   title: 'The Book',
   author: {
      name: 'Merlin Bridge',
      category: 'Fiction'
   }
} 
Object.keys(myObj).forEach(key => {
    console.log(JSON.stringify(myObj[key]));
  });