Example of custom field implementation, that stores data as object or array

[MurzNN]

Before #195 will be implemented, will be good to have some example of such field, that stores his data in supportable databases (MongoDB or PostgreSQL JSONB field) not as simple JSON text string, but as structured object.

We already have the MultiCheck field from examples/custom-fields that must do this thing, but in database it store data as simple string, here is example of MongoDB document:

{
    "_id": "5fd9e6101dab3e967f37364c",
    "name": "Super Movie",
    "rating": 4,
    "categories": "{\"Action\":true,\"Comedy\":true,\"Drama\":false}",
    "__v": 0
}

The first easy problem with current storage type is that I can't filter list of movies by category, for example to select all movies with "Comedy" category. Without this feature - categories field becomes useless.
So will be good to store same data as array, like this:

{
    "_id": "5fd9e6101dab3e967f37364c",
    "name": "Super Movie",
    "rating": 4,
    "categories": [
        "Action",
        "Comedy "
    ],
    "__v": 0
}

or via object like this:

{
    "_id": "5fd9e6101dab3e967f37364c",
    "name": "Super Movie",
    "rating": 4,
    "categories": {
        "Action": true,
        "Comedy": true,
        "Drama": false
    },
    "__v": 0
}

Also we already have examples-next/basic example, that try to implement this via fields-document field type, but this is too complex field in implementation.

So, can you extend current MultiCheck field in examples-next to implement array or object storage type (at first - maybe with easy Admin UI showing editable json in textarea), or this is not possible yet?

[MurzNN]

Here is example of how the fields-document field store the data in MongoDB document:

{
    "_id": "5fd9ede39085a0c163ae7678",
    "title": "Test document field",
    "content": {
        "document": [
            {
                "type": "paragraph",
                "children": [
                    {
                        "text": "Bold text",
                        "bold": true
                    }
                ]
            },
            {
                "type": "paragraph",
                "children": [
                    {
                        "text": " and regular text"
                    }
                ]
            }
        ]
    },
    "author": "5fd9ed8f9085a0c163ae7676",
    "__v": 0
}

[pahaz]

@MurzNN hi! We have a JSON field for such cases: https://github.com/8iq/nodejs-hackathon-boilerplate-starter-kit/tree/51a7c37/apps/_back02keystone/custom-fields/Json

And Some tests for different types of value (Object, Array, String):

• store value: https://github.com/8iq/nodejs-hackathon-boilerplate-starter-kit/blob/51a7c37/apps/_back02keystone/_api_tests/_example.test.js#L30-L96
• filter by value: https://github.com/8iq/nodejs-hackathon-boilerplate-starter-kit/blob/51a7c37/apps/_back02keystone/_api_tests/_example.test.js#L98-L192

This field is working a little differently for mongo and postgres. For example for MongoDB, the value{} and null are equal.

Schema examples:

1. https://github.com/8iq/nodejs-hackathon-boilerplate-starter-kit/blob/51a7c3766ad021fb47c13be615b38ea36fb1a1c4/apps/_back02keystone/schema/User.js#L22
2. https://github.com/8iq/nodejs-hackathon-boilerplate-starter-kit/blob/51a7c3766ad021fb47c13be615b38ea36fb1a1c4/apps/_back02keystone/schema/Test.js#L105

[MurzNN]

@pahaz, thanks for examples! But JSON field is stored in database as one single string, as I understand?

We need to store data in semantic way (as Object in MongoDB, and as separate table with relation to entity in SQL), for make filtering queries by individual JSON field values.

[pahaz]

No for mongo it's an Object and for Postgres it's jsonb.

[MurzNN]

Wow, that's great, thanks!

[pahaz]

And yes, currently we have base filter support for _in, _not_in, _equeal, _not_equal cases. In the future, we will add more cases.

[pahaz]

If you want some features you can create an issue. And 🌟 the project :)