The AdminJS Data model
Before you dive into the details of the flat helpers, let me briefly introduce the way how the database data is stored in AdminJS.
The Simple Case
On the backend all the information from DataBase tables/collections goes to {@BaseRecord#params}
object. Usually, it is a {key: value} store where key is a table name, and value could be
either a string, a number, or an instance of Date() etc.
On the Frontend - these values go to the corresponding {@link RecordJSON.params} property.
This is an example params property in the "simple case":
params: {
name: 'John',
surname: 'Doe',
age: 28,
}
The Real World Case
In the real world:
- databases have nested JSONB properties or Mixed Schemas
- developers would like to send more complicated data from the Fronted to the backend as arrays.
To achieve that we "flatten" all the data before saving them to params property.
So in the real world params could look like:
params: {
name: 'John',
surname: 'Doe',
age: 28,
// nested objects
'auth.facebook': 'some login token',
'auth.twitter': 'twitter login token',
// arrays
'interests.0': 'running',
'interests.1': 'jogging',
}
and all the data can be even nested on the deeper levels.
Why we did that?
An alternative solution would be to store an entire raw object and don't care. But there are 2 reasons why we picked this one.
1. storing selected data in the database
If you send to the ORM unflatten save request like this:
Model.save({{ auth: { facebook: 'newFacebookToken' } }})
it will override an entire auth property, so from the example above, we will lose auth.twitter.
In the second (flatten) case:
Model.save({ `auth.facebook`: 'newFacebookToken' }})
ORM should keep the value of the auth.twitter
The above is true for Mongoose adapter which is the most advanced regarding handing mixed values
2. Sending data between the Frontend and the Backend in {@link https://developer.mozilla.org/en-US/docs/Web/API/FormData FormData} format
AdminJS allows you to upload Files from the Frontend to the Backend. The most optimal way of
doing that is by using {@link https://developer.mozilla.org/en-US/docs/Web/API/FormData FormData}.
But, this requires that values for all the fields are send in [key: string]: string form.
And this, as you might guess, fits perfectly to our flatten params logic.
Consequences
Flattening in AdminJS has its consequences everywhere where you use
- {@link BaseRecord} and
- {@link RecordJSON},
because instead of raw object you have it's flatten version.
Also, (as mentioned) the payload send to the backed is also flattened.
There you should use helpers gathered in {@link flat}