type-asserted-object.ts

/**
 * Provides common `Object.` functions with additional type assertions.
 * To do this, it is assumed that the provided object doesn't have more properties (at runtime) than specified in its type.
 * Based on how the TS type system works, **this assumption cannot be made for every Object** -> the default typings are very weak.
 * @See https://github.com/microsoft/TypeScript/pull/12253#issuecomment-263132208 and https://stackoverflow.com/questions/55012174/why-doesnt-object-keys-return-a-keyof-type-in-typescript
 */
export namespace TypeAssertedObject {
    /**
     * {@link Object.entries} with additional type assertions
     * See {@link TypeAssertedObject}
     * @returns an array of key/values of the enumerable properties of an object
     */
    export function entries<T extends { [key: string]: any }>(
        object: T
    ): Exclude<
        {
            [Key in keyof T]: [Key, T[Key]];
        }[keyof T],
        undefined
    >[] {
        return Object.entries(object) as any;
    }

    /**
     * {@link Object.values} with additional type assertions
     * See {@link TypeAssertedObject}
     * @returns an array of values of the enumerable properties of an object
     */
    export function values<T extends { [key: string]: any }>(
        object: T
    ): T[keyof T][] {
        return Object.values(object);
    }

    /**
     * {@link Object.keys} with additional type assertions
     * See {@link TypeAssertedObject}
     * @returns an array of keys of the enumerable properties of an object
     */
    export function keys<T extends { [key: string]: any }>(
        object: T
    ): (keyof T)[] {
        return Object.keys(object);
    }

    /**
     * {@link Object.fromEntries} with additional type assertions
     * See {@link TypeAssertedObject}
     * @returns an object from an array of key/value pairs
     */
    export function fromEntries<K extends string, V>(objectEntries: [K, V][]) {
        return Object.fromEntries(objectEntries) as { [key in K]?: V };
    }
}