ts-cast/lib/engine/types.d.ts

Runtime typechecking

import { RuleFn } from '../rules/types';
export { RuleFn };
export type TypeGuard<T> = (value: unknown) => value is T;
export type TypeChecker = (value: unknown) => boolean;
export type ErrorReporter = (message: string, context: string | undefined, code?: string) => never;
export type NonEmptyArray<T> = [T, ...T[]];
export type ErrorMessage = {
    context: string | undefined;
    message: string;
};
export type ValidationSuccess<T> = {
    ok: true;
    result: T;
    errors: [];
};
export type ValidationFailure = {
    ok: false;
    result: undefined;
    errors: NonEmptyArray<ErrorMessage>;
};
export type ValidationResult<T> = ValidationSuccess<T> | ValidationFailure;
export interface CasterFn<T> {
    (value: unknown, context?: string, reportError?: ErrorReporter): T;
    name: string;
}
export interface Caster<T> extends CasterFn<T> {
    optional: Caster<T | undefined>;
    nullable: Caster<T | null>;
    restrict(...rules: RuleFn<Exclude<T, null | undefined>>[]): Caster<T>;
    map<D>(transform: (value: Exclude<T, null | undefined>) => D): Caster<D | Exclude<T, Exclude<T, null | undefined>>>;
    default(defaultValue: T): Caster<Exclude<T, undefined>>;
    either<Right, Left>(leftFactory: (error: TypeError) => Left, rightFactory: (value: T) => Right): CasterFn<Left | Right>;
    validation<Valid, Invalid>(invalidFactory: (errors: ErrorMessage[]) => Invalid, validFactory: (value: T) => Valid): CasterFn<Valid | Invalid>;
    validate(value: unknown): ValidationResult<T>;
    toBe<S extends T>(guard: (value: T) => value is S, typeName?: string): Caster<S>;
    toBe(predicate: (value: T) => boolean, typeName?: string): Caster<T>;
}
export interface StructCaster<S extends Record<string | symbol, any>> extends Caster<S> {
    partial: Caster<Partial<S>>;
}
export type StructSchema<S extends Record<string | symbol, any>> = {
    [field in keyof S]-?: CasterFn<S[field]>;
};
export type Tuple = {
    [index in number]: any;
};
export type TupleSchema<T extends Tuple> = {
    [index in number]: CasterFn<T[index]>;
};
type OptionalFields<T> = {
    [field in keyof T]: undefined extends T[field] ? field : never;
}[keyof T];
type RequiredFields<T> = {
    [field in keyof T]: undefined extends T[field] ? never : field;
}[keyof T];
type Resolve<T> = {
    [field in keyof T]: T[field];
};
export type OptionalUndefined<T> = Resolve<{
    [key in OptionalFields<T>]?: T[key];
} & {
    [key in RequiredFields<T>]: T[key];
}>;
export type Predicate<T> = (value: T) => boolean;
export type Guard<T, S extends T> = (value: T) => value is S;