Youtube-Plugin | A Google Chrome extension for Youtube | Browser Plugin library

Taking this from an OO approach, I would suggest you look into inheritance. The result you get from youtube and the result you get from instagram likely have some common fields such as an ID, postdate, last modified and content. Create an object that can store these common fields and call it something like SocialMediaPost. This can be used to represent every single social media post.

You can then create 2 objects specific to each network that contain the custom fields and these classes can inherit from the SocialMediaPost class. You can parse the json to the custom objects and store them in an array. Using a loop you can then cast each post to the base type and order them by the post date or something like that.