Seeking specific parameter in a JSON array using JavaScript: A guide

Currently, I am working on a project that involves retrieving Facebook news feed data using the graph API. Upon receiving the JSON object, I display it on the page. The "Likes" section is presented as an array of JSON objects like this:

data.likes:

{
    "count":2,
    "data":[
        {"name":"Jennifer Doe","id":"{user_id}"},
        {"name":"John Doe","id":"{user_id}"}
    ]
}

The main objective is to determine whether the current user has liked the post or not - assuming I have access to the current user's user_id. Therefore, I am seeking the most straightforward method to check if the current user has liked the post.

I understand that one approach could be setting up a loop and iterating through each data entry, but that may not be the most efficient solution and might not look aesthetically pleasing. Another alternative would be utilizing $.inArray() to search for a specific JSON object, however, I prefer to search based on the user_id exclusively.

I would greatly appreciate any assistance provided. Thank you in advance!

Answer №1

There are two approaches that come to mind right away:

-To use a for loop like this

for (jsonobj in data.likes.data){
  //iterate through each json object to find the user
}

-Another option is to convert the JSON object into a string using

JSON.stringify(jsonobj)

and then search for the user id within it using some method like 'search': http://www.w3schools.com/jsref/jsref_search.asp or indexOf: http://www.w3schools.com/jsref/jsref_indexof.asp.

If you require further explanation, feel free to ask.

Answer №2

An easy solution is to implement a simple for loop and utilize the javascript eval function to devise a generic method that filters out specific objects from an array based on desired criteria.

function filterArray(arr, field, val) {
  var result = [];
  for (var i = 0; i < arr.length; i++) {
    if (eval('arr[i].' + field) == val) {
      result.push(arr[i]);
    }
  }
  return result;
}

You can apply this method to your data like so:

var filteredItems = filterArray(data, 'category', selectedCategory);

This approach is versatile and can be used with any type of object...

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