type-plus/cjs/testing/test_type.d.ts

Provides additional types for TypeScript.

import type { IsAny } from '../any/any_type.js';
import type { IsArray } from '../array/array_type.js';
import type { IsBigint } from '../bigint/bigint_type.js';
import type { IsStrictBigint } from '../bigint/strict_bigint_type.js';
import type { IsBoolean } from '../boolean/boolean_type.js';
import type { IsFalse } from '../boolean/false_type.js';
import type { IsStrictBoolean } from '../boolean/strict_boolean_type.js';
import type { IsTrue } from '../boolean/true_type.js';
import type { IsEqual } from '../equal/equal.js';
import type { IsFunction } from '../function/function_type.js';
import type { IsStrictFunction } from '../function/strict_function_type.js';
import type { IsNever } from '../never/never_type.js';
import type { IsNull } from '../null/null_type.js';
import type { IsNumber } from '../number/number_type.js';
import type { IsStrictNumber } from '../number/strict_number_type.js';
import type { IsObject } from '../object/object_type.js';
import type { CanAssign, StrictCanAssign } from '../predicates/CanAssign.js';
import type { IsStrictString } from '../string/strict_string_type.js';
import type { IsString } from '../string/string_type.js';
import type { IsSymbol } from '../symbol/symbol_type.js';
import type { IsTuple } from '../tuple/tuple_type.js';
import type { IsUndefined } from '../undefined/undefined_type.js';
import type { IsUnknown } from '../unknown/unknown_type.js';
import type { IsVoid } from '../void/void_type.js';
export declare namespace testType {
    interface TestType {
        /**
         * Check if type `A` is equal to type `B` and `C`.
         *
         * @return `expected` as `A` for type inspection.
         */
        equal<A, B, C>(expected: IsEqual<A, B> & IsEqual<A, C>): A;
        /**
         * Check if type `A` is equal to type `B`.
         *
         * @return `expected` as `A` for type inspection.
         */
        equal<A, B>(expected: IsEqual<A, B>): A;
        /**
         * Check if `A` can assign to `B`.
         *
         * If `A` is a union,
         * the check is distributive.
         *
         * Meaning the result can be `boolean`,
         * meaning both `true` and `false` will pass.
         *
         * If you want to avoid the distributivity,
         * use `testType.strictCanAssign()` instead.
         *
         * @example
         * ```ts
         * testType.canAssign<123, number> // true
         *
         * testType.canAssign<number | string, number> // boolean
         * ```
         *
         * @return `expected` as `A` for type inspection.
         */
        canAssign<A, B>(expected: CanAssign<A, B>): A;
        /**
         * Check if `A` can fully assign to `B`.
         *
         * This checks all branches in an union `A` are assignable to `B`.
         *
         * @example
         * ```ts
         * testType.strictCanAssign<number | string, number | string> // true
         *
         * testType.strictCanAssign<number | string, number> // false
         * ```
         *
         * @return `expected` as `A` for type inspection.
         */
        strictCanAssign<A, B>(expected: StrictCanAssign<A, B>): A;
        /**
         * Check if type `T` is exactly `any`.
         *
         * @return `expected` as `T` for type inspection.
         */
        any<T>(expected: IsAny<T>): T;
        /**
         * Check if type `T` is exactly `array`.
         *
         * @return `expected` as `T` for type inspection.
         */
        array<T>(expected: IsArray<T>): T;
        /**
         * Check if type `T` is exactly `bigint`.
         *
         * @return `expected` as `T` for type inspection.
         */
        strictBigint<T>(expected: IsStrictBigint<T>): T;
        /**
         * Check if type `T` is `bigint` or bigint literals.
         *
         * @return `expected` as `T` for type inspection.
         */
        bigint<T>(expected: IsBigint<T>): T;
        /**
         * Check if type `T` is exactly `boolean`.
         *
         * @return `expected` as `T` for type inspection.
         */
        strictBoolean<T>(expected: IsStrictBoolean<T>): T;
        /**
         * Check if type `T` is `boolean` and boolean literals.
         *
         * @return `expected` as `T` for type inspection.
         */
        boolean<T>(expected: IsBoolean<T>): T;
        /**
         * Check if type `T` is exactly `true`.
         *
         * @return `expected` as `T` for type inspection.
         */
        true<T>(expected: IsTrue<T>): T;
        /**
         * Check if type `T` is exactly `false`.
         *
         * @return `expected` as `T` for type inspection.
         */
        false<T>(expected: IsFalse<T>): T;
        /**
         * Check if type `T` is exactly `boolean`.
         *
         * @return `expected` as `T` for type inspection.
         */
        strictFunction<T>(expected: IsStrictFunction<T>): T;
        /**
         * Check if type `T` is `boolean` and boolean literals.
         *
         * @return `expected` as `T` for type inspection.
         */
        function<T>(expected: IsFunction<T>): T;
        /**
         * Check if type `T` is exactly `never`.
         *
         * @return `expected` as `T` for type inspection.
         */
        never<T>(expected: IsNever<T>): T;
        /**
         * Check if type `T` is exactly `null`.
         *
         * @return `expected` as `T` for type inspection.
         */
        null<T>(expected: IsNull<T>): T;
        /**
         * Check if type `T` is exactly `number`.
         *
         * @return `expected` as `T` for type inspection.
         */
        strictNumber<T>(expected: IsStrictNumber<T>): T;
        /**
         * Check if type `T` is `number` or number literals.
         *
         * @return `expected` as `T` for type inspection.
         */
        number<T>(expected: IsNumber<T>): T;
        /**
         * Check if type `T` is `object`.
         *
         * Note that `Function`, `Array`, and *tuple* are also `object`.
         *
         * @return `expected` as `T` for type inspection.
         */
        object<T>(expected: IsObject<T>): T;
        /**
         * Check if type `T` is exactly `string`.
         *
         * @return `expected` as `T` for type inspection.
         */
        strictString<T>(expected: IsStrictString<T>): T;
        /**
         * Check if type `T` is `string` or string literals.
         *
         * @return `expected` as `T` for type inspection.
         */
        string<T>(expected: IsString<T>): T;
        /**
         * Check if type `T` is a `symbol`.
         *
         * @return `expected` as `T` for type inspection.
         */
        symbol<T>(expected: IsSymbol<T>): T;
        /**
         * Check if type `T` is a *tuple*.
         *
         * @return `expected` as `T` for type inspection.
         */
        tuple<T>(expected: IsTuple<T>): T;
        /**
         * Check if type `T` is exactly `undefined`.
         *
         * @return `expected` as `T` for type inspection.
         */
        undefined<T>(expected: IsUndefined<T>): T;
        /**
         * Check if type `T` is exactly `unknown`.
         *
         * @return `expected` as `T` for type inspection.
         */
        unknown<T>(expected: IsUnknown<T>): T;
        /**
         * Check if type `T` is exactly `void`.
         *
         * @return `expected` as `T` for type inspection.
         */
        void<T>(expected: IsVoid<T>): T;
        /**
         * A quick way to inspect a type.
         *
         * The handler receives a `InspectedType` object.
         * It contains `value` which is typed to `T`,
         * and many other properties to inspect the behavior of `T`.
         *
         * The handler is not being call,
         * it is use to hold the type in value for inspection.
         *
         * 🧪 *testing*
         * 🦴 *utilities*
         *
         * @example
         * ```ts
         * testType.inspect<SomeType>(t => {
         *   type T = typeof t.value // resolve and inspect the type `T`
         *   t.extend_boolean // result of `T extends boolean`
         * })
         * ```
         *
         * After trying out the type, remove the line.
         */
        inspect<T>(handler: (t: InspectedType<T>) => unknown): T;
    }
    type InspectedType<T> = {
        type: T;
        extends<R>(): T extends R ? true : false;
        extends_any: T extends any ? true : false;
        extends_unknown: T extends unknown ? true : false;
        extends_void: T extends void ? true : false;
        extends_never: T extends never ? true : false;
        extends_undefined: T extends undefined ? true : false;
        extends_null: T extends null ? true : false;
        extends_boolean: T extends boolean ? true : false;
        extends_true: T extends true ? true : false;
        extends_false: T extends false ? true : false;
        extends_number: T extends number ? true : false;
        extends_1: T extends 1 ? true : false;
        extends_bigint: T extends bigint ? true : false;
        extends_1n: T extends 1n ? true : false;
        extends_string: T extends string ? true : false;
        extends_a: T extends 'a' ? true : false;
        extends_symbol: T extends symbol ? true : false;
        extends_object: T extends object ? true : false;
        extends_function: T extends Function ? true : false;
        extends_array_unknown: T extends unknown[] ? true : false;
        extends_tuple_empty: T extends [] ? true : false;
        union<R>(): T | R;
        union_any: T | any;
        union_unknown: T | unknown;
        union_void: T | void;
        union_never: T | never;
        union_undefined: T | undefined;
        union_null: T | null;
        union_boolean: T | boolean;
        union_true: T | true;
        union_false: T | false;
        union_number: T | number;
        union_1: T | 1;
        union_bigint: T | bigint;
        union_1n: T | 1n;
        union_string: T | string;
        union_a: T | 'a';
        union_symbol: T | symbol;
        union_object: T | object;
        union_function: T | Function;
        union_array_unknown: T | unknown[];
        union_tuple_empty: T | [];
        intersect<R>(): T & R;
        intersect_any: T & any;
        intersect_unknown: T & unknown;
        intersect_void: T & void;
        intersect_never: T & never;
        intersect_undefined: T & undefined;
        intersect_null: T & null;
        intersect_boolean: T & boolean;
        intersect_true: T & true;
        intersect_false: T & false;
        intersect_number: T & number;
        intersect_1: T & 1;
        intersect_bigint: T & bigint;
        intersect_1n: T & 1n;
        intersect_string: T & string;
        intersect_a: T & 'a';
        intersect_symbol: T & symbol;
        intersect_object: T & object;
        intersect_function: T & Function;
        intersect_array_unknown: T & unknown[];
        intersect_tuple_empty: T & [];
    };
}
/**
 * Test utilities for types.
 *
 * This is designed specifically for testing.
 * The return value is the input `expected` parameter asserted as the first type parameter,
 * so that the type can be further inspected.
 */
export declare const testType: testType.TestType;
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