CODEWITHSUNDEEP
javascriptarraysjson
Tomasz Golinski
Tomasz Golinski

Reputation: 728

json - look for value and key

I'm quite new to programming and I been googling but couldn't find exactly what I'm looking for.

ok I send a request by ajax and I get response similar to this (the original json is much more complicated)

{
"shelf": {
    "genre": {
        "title1": {
            "date": "date",
            "author": "name",
            "featured": "N"
        }
        "title2": {
            "date": "date",
            "author": "name",
            "featured": "Y"
}}}

now I need to do find a "book" which is featured. So I have been looking for a way to look for featured = Y and get it's title in this case "title2".

The best way I could figure out is that when I create the json (in php) when something is featured I can create a new key => value at the same level as "shelf" 

"shelf": {
    "genre": {
        "title1": {
             /.../
        }
        "title2": {
             /.../
}}}
"featured": {
    "genre": "featuredTitle"
    "genre2":"featuredTitle2"
}}}

and then access it in javascript like this: 

response.featured['genre'];

and then get all the data by going to 

response.shelf.genre.title

but there must be a better way to do it... this gets very messy when the json is very complicated.

Thanks, Tom

Upvotes: 0

Views: 51

Answers (1)

dthree
dthree

Reputation: 20790

Almost there. You can loop through a JSON object quite easily, JSON is a very friendly format.

var genres = response.shelf.genre;

for (title in genres) {

  if (genres.hasOwnProperty(item)) {

    var bookTitle = title;
    var featured = genres[title].featured;
  }
}

The hasOwnProperty is a safety feature you should always use when looping through a JSON object. You can find out more about it here.

More on JSON

JSON solely consists of Javascript Objects and Arrays, one or the other. So even if the stack is complicated, you can always parse it by traversing either an object or an array, and so long as you know the structure of the JSON, it is easy to parse.

// Objects:
myJSON.subObject.anotherSubobject.andAnotherOne;

// Arrays:
myJSON[0]; // accesses first item in array...
myJSON.subObject[2]; // accesses third item in the subObject array.

Upvotes: 1

Related Questions