Parsing JSON for related key/value within object [duplicate]

Question

Say I have a JSON array containing an bunch of different key/values per each object. I know how to use Javascript to target a specific key/value, but what if I want to search through the entire JSON file to find an item, and then also find a related pair within that same object.

For example, how would I scan the following JSON for "Moby Dick", but then also find the author that is tied to that title?

"store": {
    "book": [ 
      { "category": "reference",
        "author": "Nigel Rees",
        "title": "Sayings of the Century",
        "price": 8.95
      },
      { "category": "fiction",
        "author": "Evelyn Waugh",
        "title": "Sword of Honour",
        "price": 12.99
      },
      { "category": "fiction",
        "author": "Herman Melville",
        "title": "Moby Dick",
        "isbn": "0-553-21311-3",
        "price": 8.99
      },
      { "category": "fiction",
        "author": "J. R. R. Tolkien",
        "title": "The Lord of the Rings",
        "isbn": "0-395-19395-8",
        "price": 22.99
      }
    ],
  }
}

Well, once you found the object whose title property is "Moby Dick", you just access its author property. And you find that object by iterating over the list of objects and compare the title property of each of them. — Felix Kling
– Felix Kling, Commented Jun 3, 2014 at 19:31

Dalorzo · Accepted Answer · 2014-06-03 19:38:43Z

2

Assuming this is your object:

var store= {
       "book": [ 
          {...}, {...}
        ]
     }

Then you can try to filter it like this:

var foundBooks = store.book.filter(function(book) { return book.title ==="Moby Dick"});

As correctly pointed out for @JLRiche foundBooks is an array. In order to access the first match it will be in the same way we do with all arrays:

var book = foundBooks[0];

edited Jun 3, 2014 at 19:38

answered Jun 3, 2014 at 19:33

Dalorzo

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2 Comments

JLRishe Over a year ago

You would need a [0] at the end or else book would be an array.

Dalorzo Over a year ago

Good point allow me to rename the result

tymeJV · Accepted Answer · 2014-06-03 19:32:48Z

0

You'd have to iterate the list, you can create some custom functions, like so:

function findTitle(title) {
    for (var i = 0; i < data.store.book.length; i++) {
        if (data.store.book[i].title == title) {
            return data.store.book[i];
        }
    }
}

So you can do:

var book = findTitle("Moby Dick"),
    author = book.author;

answered Jun 3, 2014 at 19:32

tymeJV

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Comments

Benjamin Trent · Accepted Answer · 2014-06-03 19:32:52Z

0

You would loop through your book objects and find where book.title === "Moby Dick" and then take a look at book.author for that particular object.

answered Jun 3, 2014 at 19:32

Benjamin Trent

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