get difference with previous date

I have the following JSON , how do i get difference between the previous date for num_followers for each website ?

like for website yqq on 15-02-2022 I need to get the difference between the num_followers from 14-02-2022 and update num_followers with difference value

[
    {
        "date": "2022-02-15",
        "websites": [
            {
                "website_name": "yqq",
                "num_followers": "454421"
            },
            {
                "website_name": "soundcloud",
                "num_followers": "757127"
            },
            {
                "website_name": "twitter",
                "num_followers": "21779161"
            },
            {
                "website_name": "soundcloud",
                "num_followers": "757054"
            },
            {
                "website_name": "triller",
                "num_followers": "5196"
            },
        ]
    },
    {
        "date": "2022-02-14",
        "websites": [
            {
                "website_name": "yqq",
                "num_followers": "123058219"
            },
            {
                "website_name": "triller",
                "num_followers": "5195"
            },
            {
                "website_name": "tiktok",
                "num_followers": "17100000"
            },
            {
                "website_name": "instagram",
                "num_followers": "123059626"
            },
            {
                "website_name": "tiktok",
                "num_followers": "17100000"
            },
            {
                "website_name": "tiktok",
                "num_followers": "17100000"
            },
            {
                "website_name": "soundcloud",
                "num_followers": "756956"
            },
        ]
    
    }
]