ts-essentials/dist/exact/index.d.ts

All essential TypeScript types in one place

import { AnyRecord } from "../any-record";
import { IsNever } from "../is-never";
type IsUnion<TUnion> = UnionToTuple<TUnion>["length"] extends 1 ? false : true;
type UnionToFunctionInsertion<TUnion> = (TUnion extends any ? (arg: () => TUnion) => any : never) extends (arg: infer TParam) => any ? TParam : never;
type UnionToTuple<TUnion> = UnionToFunctionInsertion<TUnion> extends () => infer TReturnType ? [...UnionToTuple<Exclude<TUnion, TReturnType>>, TReturnType] : [];
type ExactUnionLength<TValue, TShape, TValueLength = UnionToTuple<TValue>["length"], TShapeLength = UnionToTuple<TShape>["length"]> = TValueLength extends TShapeLength ? true : false;
type Xor<T, U> = T extends true ? (U extends true ? true : false) : U extends false ? true : false;
type And<TTuple> = TTuple extends [infer Head, ...infer Rest] ? Head extends true ? And<Rest> : false : TTuple extends [] ? true : false;
type ObjectKeyExact<TValue, TShape> = And<[
    IsNever<Exclude<keyof TValue, keyof TShape>>,
    IsNever<Exclude<keyof TShape, keyof TValue>>
]>;
type ObjectValueDiff<TValue, TShape> = {
    [TKey in keyof TValue]: Exclude<TValue[TKey], TShape[TKey & keyof TShape]>;
}[keyof TValue];
type ObjectValueExact<TValue, TShape> = And<[
    IsNever<ObjectValueDiff<TValue, TShape>>,
    IsNever<ObjectValueDiff<TShape, TValue>>
]>;
type ObjectExact<TValue, TShape> = [TValue] extends [TShape] ? And<[
    Xor<IsUnion<TValue>, IsUnion<TShape>>,
    ExactUnionLength<TValue, TShape>,
    ObjectKeyExact<TValue, TShape>,
    ObjectValueExact<TValue, TShape>
]> extends true ? TValue : never : never;
type IsArray<TValue> = [TValue] extends [readonly any[]] ? true : false;
type IsReadonly<TArray> = Readonly<TArray> extends TArray ? true : false;
type SameLength<TValue extends readonly any[], TShape extends readonly any[]> = IsNever<PrimitiveExact<TValue["length"], TShape["length"]>> extends true ? false : true;
type ArrayExact<TValue extends readonly any[], TShape extends readonly any[]> = And<[
    IsArray<TValue>,
    IsArray<TShape>,
    SameLength<TValue, TShape>,
    Xor<IsReadonly<TValue>, IsReadonly<TShape>>
]> extends true ? [TValue, TShape] extends [readonly (infer TValueElement)[], readonly (infer TShapeElement)[]] ? Exact<TValueElement, TShapeElement> extends TValueElement ? TValue : never : never : never;
type PrimitiveExact<TValue, TShape> = [TValue] extends [TShape] ? ([TShape] extends [TValue] ? TValue : never) : never;
export type Exact<TValue, TShape> = [TValue] extends [readonly any[]] ? [TShape] extends [readonly any[]] ? ArrayExact<TValue, TShape> : never : [TValue] extends [AnyRecord] ? ObjectExact<TValue, TShape> : PrimitiveExact<TValue, TShape>;
export {};