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Schema Type Safety

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LIVON treats schemas as the single source of truth for validation and types.

No manual transport types required​

Define the schema once, then derive everything from it:

import {object, string, number, type Infer} from '@livon/schema';

const User = object({
  name: 'User',
  shape: {
    id: string(),
    age: number().int().min(0),
  },
});

type UserType = Infer<typeof User>;

UserType is derived from the schema shape, not hand-written.

Parameters in this example​

object({...}):

  • name (string): schema node name.
  • shape (Record<string, Schema>): field schema map.

number().int().min(0):

  • min (number): minimum allowed value.

parse() = runtime validation + typed return​

Use parse() when input is unknown at runtime:

const input: unknown = JSON.parse(rawPayload);
const user = User.parse(input);

If validation fails, parse() throws a schema validation error. If validation succeeds, user is strongly typed.

Parameters in this example​

User.parse(input):

  • input (unknown): runtime value to validate and parse.

typed() = typed schema entry​

Use typed() when the value is already typed and you want the same schema entrypoint:

const typedValue: UserType = {id: 'u-1', age: 21};
const user = User.typed(typedValue);

typed() follows the schema and returns the schema output type.

Parameters in this example​

User.typed(typedValue):

  • typedValue (UserType): already-typed value passed through schema entrypoint.

End-to-end schema safety​

  1. Server operations/subscriptions are schema-defined.
  2. Client API is generated from schema AST.
  3. Payload types come from schemas end-to-end.

This keeps frontend/backend payload typing aligned without duplicating type definitions.