TypeScript Type Guard: Duck Type Equivalent To Class

duck-type-equivalent.method.ts

export interface IClassConstructor<T> {
	new (...args: any[]): T;
}

/** generic TypeScript Type Guard
 *  https://www.typescriptlang.org/docs/handbook/advanced-types.html#user-defined-type-guards
 */
export function isDuckTypeEquivalentToClass<T>(objectToTest: any, classToTest: IClassConstructor<T>): objectToTest is T {
	if (objectToTest instanceof classToTest) {
		return true;
	} else {
		const instance = new classToTest();
		for (const key in instance) {
			if (!(key in objectToTest)) {
				return false;
			}
		}
		return true;
	}
}