materializers

const materializers: <TInputRecord>(_eventDefRecord, handlers) => { [TEventName in TInputRecord[keyof TInputRecord]["name"] as Extract<TInputRecord[keyof TInputRecord], { name: TEventName }>["options"]["derived"] extends true ? never : TEventName]: Materializer<Extract<TInputRecord[keyof TInputRecord], { name: TEventName }>> }

Defined in: packages/@livestore/common/dist/schema/EventDef/materializer.d.ts:146

Builder function for creating a type-safe materializer map.

This is the primary way to define materializers in LiveStore. It ensures:

• Every non-derived event has a corresponding materializer
• Materializer argument types match their event schemas
• Derived events are excluded from the required handlers

Type Parameters

TInputRecord

TInputRecord extends Record<string, AnyWithoutFn>

Parameters

_eventDefRecord

TInputRecord

handlers

{ [TEventName in TInputRecord[keyof TInputRecord]["name"] as Extract<TInputRecord[keyof TInputRecord], { name: TEventName }>["options"]["derived"] extends true ? never : TEventName]: Materializer<Extract<TInputRecord[keyof TInputRecord], { name: TEventName }>> }

Returns

{ [TEventName in TInputRecord[keyof TInputRecord]["name"] as Extract<TInputRecord[keyof TInputRecord], { name: TEventName }>["options"]["derived"] extends true ? never : TEventName]: Materializer<Extract<TInputRecord[keyof TInputRecord], { name: TEventName }>> }

Example

import { State } from '@livestore/livestore'

const handlers = State.SQLite.materializers(events, {
  // Handler for each event - argument types are inferred
  'v1.TodoCreated': ({ id, text, completed }) =>
    tables.todos.insert({ id, text, completed }),

  'v1.TodoUpdated': ({ id, text }) =>
    tables.todos.update({ text }).where({ id }),

  // Can return multiple operations
  'v1.UserCreatedWithDefaults': ({ userId, name }) => [
    tables.users.insert({ id: userId, name }),
    tables.settings.insert({ userId, theme: 'light' }),
  ],

  // Can query current state
  'v1.TodoToggled': ({ id }, { query }) => {
    const todo = query(tables.todos.select().where({ id }).first())
    return tables.todos.update({ completed: !todo?.completed }).where({ id })
  },
})