merge_posts.js

// def merge_posts(list_of_posts: List[List[Post]]) -> List[Post]
function merge_posts(list_of_posts) {
    let posts = [];
    list_of_posts.map(val => {
        posts.concat(val);
    });

    //only uniques
    posts = posts.filter((val, index) => posts.indexOf(val) === index);

    //sort the thing
    posts.sort((l, r) => {
        if(l.created_at > r.created_at) {
            return -1;
        } else {
            if(l.id == r.created_at) {
                //break the tie
                if(l.id > r.id) return -1;
                else return 1;
            }
            return 1;
        }
    })

    let response = posts.map((val, index) => {
        return {
            id: val.id,
            description: val.description,
            image: val.image,
            created_at: cal.created_at,
        }
    })

    return response;
}