christopherbauer

type LogMessage = (message: string | JSON) => void;
/**
 * This is a defined interface for logging that closely resembles the winston logging methods. It is unlikely we will want the
 * interface itself to change (ie calling static logger.info/error/debug/etc methods) but we may want to be able
 * to swap out winston should we decide we want a different framework. With this we will
 * not depend on exposed details of the winston interface when using our logger elsewhere in the application,
 * and if we swap it out in the future it will be as simple as calling the underlying logger via the static method
 * declarations
 */
class logger {

christopherbauer

export const Retry = (count: number, waitMS: number) => {
	return function repeater(
		originalMethod: Function,
		_context: ClassMethodDecoratorContext
	) {
		function ReplacementMethod(this: any, ...args: any[]) {
			let tries = 0;
			const attempt = () => {
				tries++;
				try {

christopherbauer

import { DataAccessLayer } from "./DataAccessLayer";
import { Service } from "./Service";
import { CacheEject, CacheFlush, CacheKeys } from "./cached";

const service = new Service(new DataAccessLayer());

const id1 = service.register({ firstName: "Chris", lastName: "Bauer" });
const id2 = service.register({ firstName: "John", lastName: "Tomson" });
const id3 = service.register({ firstName: "Tom", lastName: "Johnson" });

christopherbauer

/**
 * Class method decorator for counting the number of calls
 * @param originalMethod
 * @param context
 * @returns Decorator function
 */
export const Counter = (
	originalMethod: Function,
	context: ClassMethodDecoratorContext
) => {

christopherbauer

import { DataAccessLayer } from "./DataAccessLayer";
import { Service } from "./Service";
import { CacheEject, CacheFlush, CacheKeys } from "./cached";

const service = new Service(new DataAccessLayer());

const id1 = service.register({ firstName: "Chris", lastName: "Bauer" });
const id2 = service.register({ firstName: "John", lastName: "Tomson" });
const id3 = service.register({ firstName: "Tom", lastName: "Johnson" });

christopherbauer

/**
 * Type Branding
 */
type Brand<K, T> = K & { __type: T };

/**
 * CacheKey branded type
 */
export type CacheKey = Brand<string, "CacheKey">;

christopherbauer

import { DataAccessLayer } from "./DataAccessLayer";
import { Service } from "./Service";

const service = new Service(new DataAccessLayer());

const id1 = service.register({ firstName: "Chris", lastName: "Bauer" });
const id2 = service.register({ firstName: "John", lastName: "Tomson" });
const id3 = service.register({ firstName: "Tom", lastName: "Johnson" });

console.log(service.getUserInfo(id1));

christopherbauer

import { DataAccessLayer, User } from "./DataAccessLayer";

export class Service {
	constructor(readonly dal: DataAccessLayer) {}

	register(user: User) {
		return this.dal.insertUser(user);
	}

	getUserInfo(id: number) {

christopherbauer

import { DataAccessLayer, User } from "./DataAccessLayer";

export class Service {
	constructor(readonly dal: DataAccessLayer) {}

	register(user: User) {
		return this.dal.insertUser(user);
	}

	getUserInfo(id: number) {

christopherbauer

export interface User {
	firstName: string;
	lastName: string;
}
class NotFoundError extends Error {}
export class DataAccessLayer {
	users: Record<number, User> = {};
	findUser(id: number): User {
		return this.users[id];
	}