Schema Modifiers

Schema-level modifiers extend entities with derived values and methods that are not direct stored fields.

Computed

Create a derived value from the entity. By default, computed values are not persisted.

const schema = s.define("users", {
  firstName: s.string(),
  lastName: s.string(),
}).modify(w => ({
  // Not persisted by default
  fullName: w.computed((user) => `${user.firstName} ${user.lastName}`),
}));

Tracked computed

Persist a computed value to the store for indexing/sorting and faster reads.

const schema = s.define("orders", {
  items: s.array(s.object({ price: s.number(), quantity: s.number() })),
}).modify(w => ({
  // Persisted computed field - tracked for faster reads
  total: w.computed((order) =>
    order.items.reduce((sum, i) => sum + i.price * i.quantity, 0)
  ).tracked(),
}));

Notes:

• Use .tracked() when you need to query/index by the computed value.
• Tracked fields increase write cost due to recomputation/persistence.

Function

Attach non-persisted methods to an entity.

const schema = s.define("users", {
  firstName: s.string(),
  lastName: s.string(),

  // Method is not stored; available at runtime on entity instances
  greet: s.function((user) => `Hello, ${user.firstName}!`),
});

Behavior:

• Functions are not saved to the database.
• Use functions for domain helpers and computed behavior that returns ephemeral values.