JSON - searching through keys with variable names (unknown)

Question

Total JSON noob here. I\'m trying to cycle through some JSON to pull out the first image from an array inside the object, and after 4 hours of having at it, I\'ve decided I

Answer 1

var json = JSON.parse(YOUR_JSON_STRING).custom_fields, //Fetch your JSON
    image;                                             //Pre-declare image
for(key in json){                               //Search each key in your object
    if(key.indexOf("image") != -1){             //If the index contains "image"
        image = json[key];                //Then image is set to your image array
        break;                                  //Exit the loop
    }
}
/*
image[0]  //the URL
image[1]  //the width
image[2]  //the height
image[3]  //your boolean

Answer 2

You could use for ... in

for (key in object) {
    // check match & do stuff
}

Answer 3

You can't just search through every field with a partial match, so you'll have to iterate through every field and then check the field names for the match. Try something like this:

var json = {
  "content_0_subheading": [
    "Title text"
  ],
  "content_1_text": [
    "Some text"
  ],
  "content_2_image": [
    [
      "http://staging.livelivelyblog.assemblo.com/wp-content/uploads/2013/09/wellbeing-260x130.jpg",
      260,
      130,
      true
    ]
  ],
  "content_2_caption": [
    ""
  ]
}

for (var key in json) {
    if (json.hasOwnProperty(key)) {
        if (/content_[0-9]+_image/.test(key)) {
            console.log('match!', json[key]); // do stuff here!
        }
    }
}

Basically, what we're doing is:

1) Loop through keys of json object for (var key in json)

2) Ensure the json has the property, and we're not accessing keys we don't want if (json.hasOwnProperty(key))

3) Check if key matches the regular expression /content_[0-9]+_image/

3a) Basically, test if it matches content_ANY NUMBERS_image where ANY NUMBERS is equal to at least one digit or more

4) Use that data however you please console.log(json[key])

Hope this helps!