Typia Guide Documents

Outline


// RUNTIME VALIDATORS
export function is<T>(input: unknown): input is T; // returns boolean
export function assert<T>(input: unknown): T; // throws TypeGuardError
export function assertGuard<T>(input: unknown): asserts input is T;
export function validate<T>(input: unknown): IValidation<T>; // detailed
 
// JSON FUNCTIONS
export namespace json {
  export function application<T>(): IJsonApplication; // JSON schema
  export function assertParse<T>(input: string): T; // type safe parser
  export function assertStringify<T>(input: T): string; // safe and faster
}
 
// LLM FUNCTION CALLING SCHEMA
export namespace llm {
  // collection of function calling schemas
  export function application<Class, Model>(): ILlmApplication<Class>;
  export function controller<Class, Model>(
    name: string,
    execute: Class,
  ): ILlmController<Model>; // +executor
  // structured output
  export function parameters<P, Model>(): ILlmSchema.IParameters<Model>; 
  export function schema<T, Model>(): ILlmSchema<Model>; // type schema
}
 
// PROTOCOL BUFFER
export namespace protobuf {
  export function message<T>(): string; // Protocol Buffer message
  export function assertDecode<T>(buffer: Uint8Array): T; // safe decoder
  export function assertEncode<T>(input: T): Uint8Array; // safe encoder
}
 
// RANDOM GENERATOR
export function random<T>(g?: Partial<IRandomGenerator>): T;

typia is a transformer library supporting below features:

Super-fast Runtime Validators
Enhanced JSON functions
LLM function calling schema and structured output
Protocol Buffer encoder and decoder
Random data generator

Only one line required, with pure TypeScript type

Runtime validator is 20,000x faster than class-validator

JSON serialization is 200x faster than class-transformer

Transformation

If you call typia function, it would be compiled like below.

This is the key concept of typia, transforming TypeScript type to a runtime function. The typia.is<T>() function is transformed to a dedicated type checker by analyzing the target type T in the compilation level.

This feature enables developers to ensure type safety in their applications, leveraging TypeScript’s static typing while also providing runtime validation. Instead of defining additional schemas, you can simply utilize the pure TypeScript type itself.


//----
// examples/checkString.ts
//----
import typia, { tags } from "typia";
export const checkString = typia.createIs<string>();
 
//----
// examples/checkString.js
//----
import typia from "typia";
export const checkString = (() => {
  return (input) => "string" === typeof input;
})();

Outline

Transformation

Sponsors