Error: 3 INVALID_ARGUMENT: Cannot convert an array value in an array value in Firestore admin

Question

I am trying to save multiple tweet objects retrieved using the twitter api in my firstore db, but I am getting this error:

Error: 3 INVALID_ARGUMENT: Cannot convert an array value in an array value

Below is the sample JSON object: all tweet objects are similar to this

TweetObj: {
  "created_at": "Wed Feb 12 15:17:24 +0000 2020",
  "id": 1227612675334660000,
  "id_str": "1227612675334660099",
  "full_text": "Writing online is a superpower.\n\nHere’s a list of people who should start writing online.\n\n1. The Niche Hobbyist\n\nThe Internet rewards people with obscure interests. Writing online will help you find other like-minded hobbyists who you wouldn’t be able to find in real-life.",
  "truncated": false,
  "display_text_range": [
    0,
    274
  ],
  "entities": {
    "hashtags": [],
    "symbols": [],
    "user_mentions": [],
    "urls": []
  },
  "source": "<a href=\"http://twitter.com/download/iphone\" rel=\"nofollow\">Twitter for iPhone</a>",
  "in_reply_to_status_id": null,
  "in_reply_to_status_id_str": null,
  "in_reply_to_user_id": null,
  "in_reply_to_user_id_str": null,
  "in_reply_to_screen_name": null,
  "user": {
    "id": 240049622,
    "id_str": "240049622",
    "name": "David Perell",
    "screen_name": "david_perell",
    "location": "New York",
    "description": "\"The Writing Guy\" | I tweet about business, online learning, and Internet writing | My Podcast:  | My writing school: ,
    "url": "",
    "entities": {
      "url": {
        "urls": [
          {
            "url": ,
            "expanded_url": "http://www.perell.com/",
            "display_url": "perell.com",
            "indices": [
              0,
              23
            ]
          }
        ]
      },
      "description": {
        "urls": [
          {
            "url": "",
            "expanded_url": "http://Perell.com/podcast",
            "display_url": "Perell.com/podcast",
            "indices": [
              96,
              119
            ]
          },
          {
            "url": "",
            "expanded_url": "http://writeofpassage.school",
            "display_url": "writeofpassage.school",
            "indices": [
              141,
              164
            ]
          }
        ]
      }
    },
    "protected": false,
    "followers_count": 89464,
    "friends_count": 763,
    "listed_count": 1539,
    "created_at": "Wed Jan 19 01:41:27 +0000 2011",
    "favourites_count": 51075,
    "utc_offset": null,
    "time_zone": null,
    "geo_enabled": true,
    "verified": false,
    "statuses_count": 21700,
    "lang": null,
    "contributors_enabled": false,
    "is_translator": false,
    "is_translation_enabled": false,
    "profile_background_color": "C0DEED",
    "profile_background_image_url": "http://abs.twimg.com/images/themes/theme1/bg.png",
    "profile_background_image_url_https": "https://abs.twimg.com/images/themes/theme1/bg.png",
    "profile_background_tile": false,
    "profile_image_url": "http://pbs.twimg.com/profile_images/913816689892044800/rF7O3Bfz_normal.jpg",
    "profile_image_url_https": "https://pbs.twimg.com/profile_images/913816689892044800/rF7O3Bfz_normal.jpg",
    "profile_banner_url": "https://pbs.twimg.com/profile_banners/240049622/1543613054",
    "profile_link_color": "129CE6",
    "profile_sidebar_border_color": "C0DEED",
    "profile_sidebar_fill_color": "DDEEF6",
    "profile_text_color": "333333",
    "profile_use_background_image": true,
    "has_extended_profile": true,
    "default_profile": false,
    "default_profile_image": false,
    "following": true,
    "follow_request_sent": false,
    "notifications": true,
    "translator_type": "none"
  },
  "geo": null,
  "coordinates": null,
  "place": {
    "id": "01a9a39529b27f36",
    "url": "https://api.twitter.com/1.1/geo/id/01a9a39529b27f36.json",
    "place_type": "city",
    "name": "Manhattan",
    "full_name": "Manhattan, NY",
    "country_code": "US",
    "country": "United States",
    "contained_within": [],
    "bounding_box": {
      "type": "Polygon",
      "coordinates": [
        [
          [
            -74.026675,
            40.683935
          ],
          [
            -73.910408,
            40.683935
          ],
          [
            -73.910408,
            40.877483
          ],
          [
            -74.026675,
            40.877483
          ]
        ]
      ]
    },
    "attributes": {}
  },
  "contributors": null,
  "is_quote_status": false,
  "retweet_count": 357,
  "favorite_count": 2145,
  "favorited": false,
  "retweeted": false,
  "lang": "en"
}

Above is the exact object that is giving the error In the above snippet, the argument threads is an array containing multiple tweet objects just like the one described earlier.

Help would be very much appreciated.

Answer 1

You could try to transparently serialize/unserialize your Tweet in order to:

• convert all arrays to objects before saving in Firestore
• convert all objects which keys are numeric-ish to arrays after retrieving a record from firestore

Depending on which data is supposed to be indexed and queried, you could also use JSON.stringify() on some parts of the record which structure is not supported by Firestore.

Answer 2

I got the exact same error from Firestore admin, while handling complex JSON objects like yours.

The problem came down to the fact that some fields contain nested arrays. Triple-nested in your case, like for your bounding_box.coordinates field.

I my case, I flattened the JSON object structure (transforming nested arrays into simple vectors) before pushing it to Firestore, but you could also "stringify" the multi-dimensional arrays (using JSON.stringify) and parse it back (JSON.parse) when retrieving these specific fields.