export enum ObjectErrorCode {
    NOT_OBJECT = "NOT_OBJECT"
}

export function checkObject (mixed : any) : undefined|ObjectErrorCode {
    if (mixed instanceof Object) {
        return undefined;
    } else {
        return ObjectErrorCode.NOT_OBJECT;
    }
}

export function checkObjectPredicate<ErrorT> (mixed : any, predicate : (obj : Object) => undefined|ErrorT) : undefined|ObjectErrorCode|ErrorT {
    const error = checkObject(mixed);
    if (error !== undefined) {
        return error;
    }

    return predicate(mixed);
}