Field Hooks

Field-level hooks offer incredible potential for encapsulating your logic. They help to isolate concerns and package up functionalities to be easily reusable across your projects.

Example use cases include:

  • Automatically add an owner relationship to a Document based on the req.user.id
  • Encrypt / decrypt a sensitive field using beforeValidate and afterRead hooks
  • Auto-generate field data using a beforeValidate hook
  • Format incoming data such as kebab-casing a document slug with beforeValidate
  • Restrict updating a document to only once every X hours using the beforeChange hook

All field types provide the following hooks:

  • beforeValidate
  • beforeChange
  • afterChange
  • afterRead

Config

Example field configuration:

{
name: 'name',
label: 'Name',
type: 'text',
hooks: {
beforeValidate: [(args) => {...}],
beforeChange: [(args) => {...}],
afterChange: [(args) => {...}],
afterRead: [(args) => {...}],
}
}

Arguments and return values

All field-level hooks are formatted to accept the same arguments, although some arguments may be undefined based on which field hook you are utilizing.

Arguments

Field Hooks receive one args argument that contains the following properties:

OptionDescription
valueThe value of the field, before any updating. Will return undefined within create operations.
dataThe data passed to update the field with in create and update operations.
originalDocThe full original document in update or read operations.
operationA string relating to which operation the field type is currently executing within.
reqThe Express request object. It is mocked for Local API operations.

Return value

All field hooks can optionally modify the return value of the field before the operation continues. Field Hooks may optionally return the value that should be used within the field.

Next

Global Hooks