feathers-schema

FeathersJS Schemas & Resolvers

Schemas and resolvers are database-independent. A schema (TypeBox) defines shape, derives the TS type, and validates. A resolver transforms property values against the hook context. They are applied through the schemaHooks registered in the service file (see feathers-service).

The four kinds — what each is for

• Result (<name>Resolver): shapes data being returned; the place to populate associations / virtual properties.
• Data (<name>DataResolver): runs on create/update/patch data before saving; set defaults, computed values, hash passwords, stamp createdAt.
• Query (<name>QueryResolver): validates/coerces the query string and is the right place to restrict which records a user may touch (row-level security).
• External (<name>ExternalResolver): produces the safe, outward-facing version — hide sensitive fields here (e.g. password).

Defining the schema

import { resolve, virtual } from '@feathersjs/schema'
import { Type, getValidator, querySyntax } from '@feathersjs/typebox'
import type { Static } from '@feathersjs/typebox'
import type { HookContext } from '../../declarations'
import { dataValidator, queryValidator } from '../../validators'

export const messageSchema = Type.Object(
  {
    id: Type.Number(),            // MongoDB: _id: ObjectIdSchema()
    text: Type.String(),
    createdAt: Type.Number(),
    userId: Type.Number(),
    user: Type.Ref(userSchema)    // associated, populated by a virtual resolver
  },
  { $id: 'Message', additionalProperties: false }
)
export type Message = Static<typeof messageSchema>   // type derived from schema — single source of truth
export const messageValidator = getValidator(messageSchema, dataValidator)

$id must be globally unique. additionalProperties: false rejects unknown fields. Get the TS type with Static<typeof ...> — never hand-maintain a parallel interface.

Useful TypeBox helpers: Type.Optional(...), Type.Pick(schema, [...]), Type.Partial(schema) (for patch), Type.Intersect([...]), Type.Ref(otherSchema) for associations.