typia

What is typia?

Typia is a TypeScript library that provides runtime type checking, validation, and serialization/deserialization capabilities. It aims to enhance type safety and runtime validation for TypeScript applications.

What are typia's main functionalities?

Runtime Type Checking

This feature allows you to perform runtime type checking to ensure that a value matches a specified TypeScript type. The code sample demonstrates how to check if a value is a string at runtime.

const isString = typia.is<string>(value);

Validation

Typia provides validation capabilities to ensure that data conforms to a specified type. The code sample shows how to validate an object against a TypeScript type, returning a result that indicates whether the data is valid.

const validationResult = typia.validate<MyType>(data);

Serialization/Deserialization

Typia can serialize TypeScript objects to JSON strings and deserialize JSON strings back to TypeScript objects, ensuring type safety throughout the process. The code sample demonstrates both serialization and deserialization.

const jsonString = typia.stringify<MyType>(data); const dataObject = typia.parse<MyType>(jsonString);

Other packages similar to typia

io-ts

io-ts is a runtime type system for IO decoding/encoding in TypeScript. It provides similar functionality to typia in terms of runtime type checking and validation. However, io-ts uses a functional programming approach and is more focused on decoding and encoding data.

zod

Zod is a TypeScript-first schema declaration and validation library. It offers similar validation and type-checking capabilities as typia but with a more declarative API for defining schemas. Zod is known for its simplicity and ease of use.

class-validator

Class-validator is a library for validating TypeScript class objects. It provides decorators for defining validation rules directly in class definitions. While it focuses on class-based validation, typia offers a broader range of type-related utilities.

README

Typia

// RUNTIME VALIDATORS
export function is<T>(input: unknown | T): input is T; // returns boolean
export function assert<T>(input: unknown | T): T; // throws TypeGuardError
export function validate<T>(input: unknown | T): IValidation<T>; // detailed

// STRICT VALIDATORS
export function equals<T>(input: unknown: T): input is T;
export function assertEquals<T>(input: unknown | T): T;
export function validateEquals<T>(input: unknown | T): IValidation<T>;

// 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
    // +) isParse, validateParse 
    // +) stringify, isStringify, validateStringify

typia is a transformer library of TypeScript, supporting below features:

• Super-fast Runtime Validators
• Safe JSON parse and fast stringify functions
• JSON schema generator

All functions in typia require only one line. You don't need any extra dedication like JSON schema definitions or decorator function calls. Just call typia function with only one line like typia.assert<T>(input).

Also, as typia performs AOT (Ahead of Time) compilation skill, its performance is much faster than other competitive libaries. For an example, when comparing validate function is() with other competitive libraries, typia is maximum 15,000x times faster than class-validator.

Measured on Intel i5-1135g7, Surface Pro 8

Setup

Setup Wizard

npx typia setup

Just type npx typia setup, that's all.

After the setup, you can compile typia utilized code by using ttsc (ttypescript) command. If you want to run your TypeScript file directly through ts-node, add -C ttypescript argument like below:

# COMPILE THROUGH TTYPESCRIPT
npx ttsc

# RUN TS-NODE WITH TTYPESCRIPT
npx ts-node -C ttypescript src/index.ts

Manual Setup

If you want to install and setup typia manually, read Guide Documents - Setup.

• Setup Wizard
• NPM Packages
• tsconfig.json
• vite
• webpack

vite

When you want to setup typia on your frontend project with vite, just configure vite.config.ts like below.

For reference, don't forget running Setup Wizard before.

import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";
import typescript from "@rollup/plugin-typescript";
import ttsc from "ttypescript";

// https://vitejs.dev/config/
export default defineConfig({
  plugins: [
    react(),
    typescript({
      typescript: ttsc,
    })
  ]
});

Features

In here README documents, only summarized informations are provided.

For more details, refer to the Guide Documents (wiki).

• Runtime Validators
  • powerful validator
  • is() function
  • assert() function
  • validate() function
  • strict validators
  • factory functions
  • comment tags
• Enhanced JSON
  • JSON schema
  • parse() functions
  • stringify() functions
  • comment tags

Runtime Validators

// ALLOW SUPERFLUOUS PROPERTIES
export function is<T>(input: T | unknown): input is T; // returns boolean
export function assert<T>(input: T | unknown): T; // throws `TypeGuardError`
export function validate<T>(input: T | unknown): IValidation<T>; // detailed

// DO NOT ALLOW SUPERFLUOUS PROPERTIES
export function equals<T>(input: T | unknown): boolean;
export function assertEquals<T>(input: T | unknown): T;
export function validateEquals<T>(input: T | unknown): IValidation<T>;

// REUSABLE FACTORY FUNCTIONS
export function createIs<T>(): (input: unknown) => T;
export function createAssert<T>(): (input: unknown) => T;
export function createValidate<T>(): (input: unknown) => IValidation<T>;
export function createEquals<T>(): (input: unknown) => boolean;
export function createAssertEquals<T>(): (input: unknown) => T;
export function createValidateEquals<T>(): (input: unknown) => IValidation<T>;

typia supports three type of validator functions:

• is(): returns false if not matched with the type T
• assert(): throws a TypeGuardError when not matched
• validate()
  • when matched, returns IValidation.ISuccess<T> with value property
  • when not matched, returns IValidation.IFailure with errors property

Also, if you want more strict validator functions that even do not allowing superfluous properties not written in the type T, you can use those functions instead; equals(), assertEquals(), validateEquals(). Otherwise you want to create resuable validator functions, you can utilize factory functions like createIs() instead.

When you want to add special validation logics, like limiting range of numeric values, you can do it through comment tags. If you want to know about it, visit the Guide Documents (Features > Runtime Validators > Comment Tags).

Enhanced JSON

// JSON SCHEMA GENERATOR
export function application<
    Types extends unknown[],
    Purpose extends "swagger" | "ajv" = "swagger",
    Prefix extends string = Purpose extends "swagger"
        ? "#/components/schemas"
        : "components#/schemas",
>(): IJsonApplication;

// SAFE PARSER FUNCTIONS
export function isParse<T>(input: string): T | null;
export function assertParse<T>(input: string): T;
export function validateParse<T>(input: string): IValidation<T>;

// FASTER STRINGIFY FUNCTIONS
export function stringify<T>(input: T): string; // unsafe
export function isStringify<T>(input: T): string | null; // safe
export function assertStringify<T>(input: T): string;
export function validateStringify<T>(input: T): IValidation<string>;

// FACTORY FUNCTIONS
export function createAssertParse<T>(): (input: string) => T;
export function createAssertStringify<T>(): (input: T) => string;
    // +) createIsParse, createValidateParse
    // +) createStringify, createIsStringify, createValidateStringify

typia supports enhanced JSON functions.

• application(): generate JSON schema with only one line
  • you can complement JSON schema contents through comment tags
• assertParse(): parse JSON string safely with type validation
• isStringify(): maximum 10x faster JSON stringify fuction even type safe

Measured on AMD R7 5800H

Appendix

Nestia

https://github.com/samchon/nestia

Automatic SDK and Swagger generator for NestJS, evolved than ever.

nestia is an evolved SDK and Swagger generator, which analyzes your NestJS server code in the compilation level. With nestia and compilation level analyzer, you don't need to write any swagger or class-validator decorators.

Reading below table and example code, feel how the "compilation level" makes nestia stronger.

Components	nestia::SDK	nestia::swagger	@nestjs/swagger
Pure DTO interface	✔	✔	❌
Description comments	✔	✔	❌
Simple structure	✔	✔	✔
Generic type	✔	✔	❌
Union type	✔	✔	▲
Intersection type	✔	✔	▲
Conditional type	✔	▲	❌
Auto completion	✔	❌	❌
Type hints	✔	❌	❌
5x faster JSON.stringify()	✔	❌	❌
Ensure type safety	✅	❌	❌

// IMPORT SDK LIBRARY GENERATED BY NESTIA
import api from "@samchon/shopping-api";
import { IPage } from "@samchon/shopping-api/lib/structures/IPage";
import { ISale } from "@samchon/shopping-api/lib/structures/ISale";
import { ISaleArticleComment } from "@samchon/shopping-api/lib/structures/ISaleArticleComment";
import { ISaleQuestion } from "@samchon/shopping-api/lib/structures/ISaleQuestion";

export async function trace_sale_question_and_comment
    (connection: api.IConnection): Promise<void>
{
    // LIST UP SALE SUMMARIES
    const index: IPage<ISale.ISummary> = await api.functional.shoppings.sales.index
    (
        connection,
        "general",
        { limit: 100, page: 1 }
    );

    // PICK A SALE
    const sale: ISale = await api.functional.shoppings.sales.at
    (
        connection, 
        index.data[0].id
    );
    console.log("sale", sale);

    // WRITE A QUESTION
    const question: ISaleQuestion = await api.functional.shoppings.sales.questions.store
    (
        connection,
        "general",
        sale.id,
        {
            title: "How to use this product?",
            body: "The description is not fully enough. Can you introduce me more?",
            files: []
        }
    );
    console.log("question", question);

    // WRITE A COMMENT
    const comment: ISaleArticleComment = await api.functional.shoppings.sales.comments.store
    (
        connection,
        "general",
        sale.id,
        question.id,
        {
            body: "p.s) Can you send me a detailed catalogue?",
            anonymous: false
        }
    );
    console.log("comment", comment);
}

Nestia-Helper

https://github.com/samchon/nestia-helper

Helper library of NestJS, using this typia.

nestia-helper is a helper library of NestJS, which boosts up the JSON.stringify() speed 5x times faster about the API responses, automatically. Also, nestia-helper supports automatic validation of request body, that is maximum 15,000x times faster than legacy class-validator too.

import helper from "nestia-helper";
import * as nest from "@nestjs/common";

@nest.Controller("bbs/articles")
export class BbsArticlesController
{
    // automatic typia.stringify() for response body
    @helper.TypedRoute.Get()
    public store(
        // automatic typia.assert() for request body
        @helper.TypedBody() input: IBbsArticle.IStore
    ): Promise<IBbsArticle>;
}