just ts typing experiement

just.ts

import { any } from 'ramda';

class DbError extends Error {
    constructor(message: string) {
        super(message);
        // Set the prototype explicitly.
        Object.setPrototypeOf(this, DbError.prototype);
    }
}

class CacheError extends Error {
    constructor(message: string) {
        super(message);
        // Set the prototype explicitly.
        Object.setPrototypeOf(this, CacheError.prototype);
    }
}

class CertError extends Error {
    constructor(message: string) {
        super();
        this.message = message;
    }
}

type BadRequest = DbError | CacheError;
type Forbidden = CertError;
const badRequestTypes = [DbError, CacheError];

function isBadRequest(x: any): x is BadRequest {
    return any(c => x instanceof c, badRequestTypes);
}

const dbError = new DbError('DbError');
const cacheError = new CacheError('CacheError');
const certError = new CertError('CertError');

console.log(dbError instanceof DbError);
console.log(cacheError instanceof CacheError);
console.log(certError instanceof DbError);
console.log(`isBadRequest: ${isBadRequest(dbError)}`);
console.log(`isBadRequest: ${isBadRequest(cacheError)}`);
// console.log(typeof certError);
// console.log("kk");