TypeBox Extensions

TypeBox extensions (typebox-x) is a utility library based around the sinclairzx81/typebox schema builder and validation library.

Features

• Validate and coerce environment variables (like t3-env).
• Additional kinds and shorthands, e.g. t.UUID.
• Built in configuration for common formats, e.g. date, email, uri.
• Built in support for NestJS

Install

pnpm add @jcwillox/typebox-x @sinclair/typebox

Load envs

First import the createEnv function, then pass it a typebox schema.

The createEnv function uses the clean, convert, default and decode function from typebox to parse you environment variables.

This means that it will strip extra keys, set default values, attempt to convert values to the destination type, e.g. "true" -> true, and then decode/check the value.

import { createEnv } from "@jcwillox/typebox-x";

const env = createEnv(
  t.Object({
    APP_ENV: t.Optional(t.String()),
    NODE_ENV: t.String({ default: "development" }),
    BOOL_FLAG: t.Boolean(),
  }),
);

console.log(env.BOOL_FLAG === true); // -> true

Variants

Nullable

• Wraps schema in a union with null.

  t.Nullable(t.String());
  // t.Union([t.String(), t.Null()]);

Nullish

• Wraps schema in an optional union with null.

  t.Nullish(t.String());
  // t.Optional(t.Union([t.String(), t.Null()]));

UUID

• Shorthand for string of format uuid.

  t.UUID();
  // t.String({ format: "uuid" })

DateString

• Uses Transform to convert a string to a Date object when decoding and from a Date object to a string when encoding.

  t.DateString();

RecordString

• A replacement for t.Record that uses t.String as the key type, and adds the additionalProperties property, for backwards compatibility with OpenAPI 3.0.

  t.RecordString(t.Object({ one: t.String() }));
  // Record<string, {a: string}>

  Equivalent to:

  t.Record(t.String(), schema, {
    additionalProperties: schema,
  });

StringEnum

• Creates a union of strings with a enum schema representation

  t.StringEnum(["one", "two"]);

LiteralEnum

• Drop-in replacement for t.Literal that adds the type and enum properties, for backwards compatibility with OpenAPI 3.0.
• You should override Literal with this function, for OpenAPI 3.0 compatibility.

  t.LiteralEnum("one");

Formats

Simply import @jcwillox/typebox-x/formats before you perform any validations, usually you'll want to do this in you entrypoint. If a format is already defined with the same name, it will not be overwritten.

import "@jcwillox/typebox-x/formats";

NestJS

Use the typebox prefixed method decorators and provide the corresponding schemas.

import { Controller } from "@nestjs/common";
import { t } from "@jcwillox/typebox-x";
import { TypeboxGet } from "@jcwillox/typebox-x/nestjs";
// or if you prefer we also export non-prefixed methods
// import { Get } from "@jcwillox/typebox-x/nestjs";

@Controller()
export class AppController {
  @TypeboxGet(":my_id", {
    query: t.Object({
      limit: t.Optional(t.Integer({ default: 10 })),
    }),
    params: {
      my_id: t.UUID(),
    },
    response: t.Object({
      message: t.String(),
    }),
  })
  getHello() {
    return { message: "Hello World!" };
  }
}

You'll likely want to define your schemas outside the @TypeboxGet decorator, so you can also infer types from them, using Static<typeof schema>.

import { Controller, Param, Query } from "@nestjs/common";
import { t } from "@jcwillox/typebox-x";
import { TypeboxGet } from "@jcwillox/typebox-x/nestjs";
import { Static } from "@sinclair/typebox";

type Query = Static<typeof QuerySchema>;
const QuerySchema = t.Object({
  limit: t.Optional(t.Integer({ default: 10 })),
});

type Response = Static<typeof ResponseSchema>;
const ResponseSchema = t.Object({
  message: t.String(),
});

@Controller()
export class AppController {
  @TypeboxGet(":my_id", {
    query: QuerySchema,
    params: { my_id: t.UUID() },
    response: ResponseSchema,
  })
  getHello(@Param("my_id") myId: string, @Query() query: Query): Response {
    return { message: "Hello World!" };
  }
}