veffect
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powerful TypeScript validation library built on the robust foundation of Effect combining exceptional type safety, high performance, and developer experience. Taking inspiration from Effect's functional principles, VEffect delivers a balanced approach tha
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TypeScript
/**
* This module provides types and utility functions to create and work with branded types,
* which are TypeScript types with an added type tag to prevent accidental usage of a value in the wrong context.
*
* The `refined` and `nominal` functions are both used to create branded types in TypeScript.
* The main difference between them is that `refined` allows for validation of the data, while `nominal` does not.
*
* The `nominal` function is used to create a new branded type that has the same underlying type as the input, but with a different name.
* This is useful when you want to distinguish between two values of the same type that have different meanings.
* The `nominal` function does not perform any validation of the input data.
*
* On the other hand, the `refined` function is used to create a new branded type that has the same underlying type as the input,
* but with a different name, and it also allows for validation of the input data.
* The `refined` function takes a predicate that is used to validate the input data.
* If the input data fails the validation, a `BrandErrors` is returned, which provides information about the specific validation failure.
*
* @since 2.0.0
*/
import * as Either from "./Either.js";
import * as Option from "./Option.js";
import type { Predicate } from "./Predicate.js";
import type * as Types from "./Types.js";
/**
* @since 2.0.0
* @category symbols
*/
export declare const BrandTypeId: unique symbol;
/**
* @since 2.0.0
* @category symbols
*/
export type BrandTypeId = typeof BrandTypeId;
/**
* @since 2.0.0
* @category symbols
*/
export declare const RefinedConstructorsTypeId: unique symbol;
/**
* @since 2.0.0
* @category symbols
*/
export type RefinedConstructorsTypeId = typeof RefinedConstructorsTypeId;
/**
* A generic interface that defines a branded type.
*
* @since 2.0.0
* @category models
*/
export interface Brand<in out K extends string | symbol> {
readonly [BrandTypeId]: {
readonly [k in K]: K;
};
}
/**
* @since 2.0.0
*/
export declare namespace Brand {
/**
* Represents a list of refinement errors.
*
* @since 2.0.0
* @category models
*/
interface BrandErrors extends ReadonlyArray<RefinementError> {
}
/**
* Represents an error that occurs when the provided value of the branded type does not pass the refinement predicate.
*
* @since 2.0.0
* @category models
*/
interface RefinementError {
readonly meta: unknown;
readonly message: string;
}
/**
* @since 2.0.0
* @category models
*/
interface Constructor<in out A extends Brand<any>> {
readonly [RefinedConstructorsTypeId]: RefinedConstructorsTypeId;
/**
* Constructs a branded type from a value of type `A`, throwing an error if
* the provided `A` is not valid.
*/
(args: Brand.Unbranded<A>): A;
/**
* Constructs a branded type from a value of type `A`, returning `Some<A>`
* if the provided `A` is valid, `None` otherwise.
*/
option(args: Brand.Unbranded<A>): Option.Option<A>;
/**
* Constructs a branded type from a value of type `A`, returning `Right<A>`
* if the provided `A` is valid, `Left<BrandError>` otherwise.
*/
either(args: Brand.Unbranded<A>): Either.Either<A, Brand.BrandErrors>;
/**
* Attempts to refine the provided value of type `A`, returning `true` if
* the provided `A` is valid, `false` otherwise.
*/
is(a: Brand.Unbranded<A>): a is Brand.Unbranded<A> & A;
}
/**
* A utility type to extract a branded type from a `Brand.Constructor`.
*
* @since 2.0.0
* @category models
*/
type FromConstructor<A> = A extends Brand.Constructor<infer B> ? B : never;
/**
* A utility type to extract the value type from a brand.
*
* @since 2.0.0
* @category models
*/
type Unbranded<P> = P extends infer Q & Brands<P> ? Q : P;
/**
* A utility type to extract the brands from a branded type.
*
* @since 2.0.0
* @category models
*/
type Brands<P> = P extends Brand<any> ? Types.UnionToIntersection<{
[k in keyof P[BrandTypeId]]: k extends string | symbol ? Brand<k> : never;
}[keyof P[BrandTypeId]]> : never;
/**
* A utility type that checks that all brands have the same base type.
*
* @since 2.0.0
* @category models
*/
type EnsureCommonBase<Brands extends readonly [Brand.Constructor<any>, ...Array<Brand.Constructor<any>>]> = {
[B in keyof Brands]: Brand.Unbranded<Brand.FromConstructor<Brands[0]>> extends Brand.Unbranded<Brand.FromConstructor<Brands[B]>> ? Brand.Unbranded<Brand.FromConstructor<Brands[B]>> extends Brand.Unbranded<Brand.FromConstructor<Brands[0]>> ? Brands[B] : Brands[B] : "ERROR: All brands should have the same base type";
};
}
/**
* @category alias
* @since 2.0.0
*/
export type Branded<A, K extends string | symbol> = A & Brand<K>;
/**
* Returns a `BrandErrors` that contains a single `RefinementError`.
*
* @since 2.0.0
* @category constructors
*/
export declare const error: (message: string, meta?: unknown) => Brand.BrandErrors;
/**
* Takes a variable number of `BrandErrors` and returns a single `BrandErrors` that contains all refinement errors.
*
* @since 2.0.0
* @category constructors
*/
export declare const errors: (...errors: Array<Brand.BrandErrors>) => Brand.BrandErrors;
/**
* Returns a `Brand.Constructor` that can construct a branded type from an unbranded value using the provided `refinement`
* predicate as validation of the input data.
*
* If you don't want to perform any validation but only distinguish between two values of the same type but with different meanings,
* see {@link nominal}.
*
* @param refinement - The refinement predicate to apply to the unbranded value.
* @param onFailure - Takes the unbranded value that did not pass the `refinement` predicate and returns a `BrandErrors`.
*
* @example
* import * as Brand from "effect/Brand"
*
* type Int = number & Brand.Brand<"Int">
*
* const Int = Brand.refined<Int>(
* (n) => Number.isInteger(n),
* (n) => Brand.error(`Expected ${n} to be an integer`)
* )
*
* assert.strictEqual(Int(1), 1)
* assert.throws(() => Int(1.1))
*
* @since 2.0.0
* @category constructors
*/
export declare function refined<A extends Brand<any>>(f: (unbranded: Brand.Unbranded<A>) => Option.Option<Brand.BrandErrors>): Brand.Constructor<A>;
export declare function refined<A extends Brand<any>>(refinement: Predicate<Brand.Unbranded<A>>, onFailure: (unbranded: Brand.Unbranded<A>) => Brand.BrandErrors): Brand.Constructor<A>;
/**
* This function returns a `Brand.Constructor` that **does not apply any runtime checks**, it just returns the provided value.
* It can be used to create nominal types that allow distinguishing between two values of the same type but with different meanings.
*
* If you also want to perform some validation, see {@link refined}.
*
* @example
* import * as Brand from "effect/Brand"
*
* type UserId = number & Brand.Brand<"UserId">
*
* const UserId = Brand.nominal<UserId>()
*
* assert.strictEqual(UserId(1), 1)
*
* @since 2.0.0
* @category constructors
*/
export declare const nominal: <A extends Brand<any>>() => Brand.Constructor<A>;
/**
* Combines two or more brands together to form a single branded type.
* This API is useful when you want to validate that the input data passes multiple brand validators.
*
* @example
* import * as Brand from "effect/Brand"
*
* type Int = number & Brand.Brand<"Int">
* const Int = Brand.refined<Int>(
* (n) => Number.isInteger(n),
* (n) => Brand.error(`Expected ${n} to be an integer`)
* )
* type Positive = number & Brand.Brand<"Positive">
* const Positive = Brand.refined<Positive>(
* (n) => n > 0,
* (n) => Brand.error(`Expected ${n} to be positive`)
* )
*
* const PositiveInt = Brand.all(Int, Positive)
*
* assert.strictEqual(PositiveInt(1), 1)
* assert.throws(() => PositiveInt(1.1))
*
* @since 2.0.0
* @category combining
*/
export declare const all: <Brands extends readonly [Brand.Constructor<any>, ...Array<Brand.Constructor<any>>]>(...brands: Brand.EnsureCommonBase<Brands>) => Brand.Constructor<Types.UnionToIntersection<{
[B in keyof Brands]: Brand.FromConstructor<Brands[B]>;
}[number]> extends infer X extends Brand<any> ? X : Brand<any>>;
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