// We can start to use deltas to express relational data in a given context import express from "express"; import { bindPublish, } from "./pub-sub"; import { runDeltas } from "./deltas"; import { Entities, Entity } from "./object-layer"; import { bindReply, runRequestHandlers } from "./request-reply"; import { subscribeToSeeds } from "./peers"; import { ENABLE_HTTP_API, HTTP_API_ADDR, HTTP_API_PORT } from "./config"; // As an app we want to be able to write and read data. // The data is whatever shape we define it to be in a given context. // So we want access to an API that is integrated with our declarations of // e.g. entities and their properties. // This implies at least one layer on top of the underlying primitive deltas. type UserProperties = { id?: string; name: string; nameLong?: string; email?: string; age: number; }; class Users { db = new Entities(); create(properties: UserProperties): Entity { // We provide undefined for the id, to let the database generate it // This call returns the id const user = this.db.put(undefined, properties); console.log(`Users.create(${user.id}, ${JSON.stringify(properties)}`); return user; } upsert(properties: UserProperties): Entity { const user = this.db.put(properties.id, properties); console.log(`Users.upsert(${user.id}, ${JSON.stringify(properties)}`); return user; } getOne(id: string): Entity | undefined { return this.db.get(id); } getIds(): string[] { return this.db.getIds(); } } (async () => { const app = express() app.get("/ids", (req: express.Request, res: express.Response) => { res.json({ ids: users.getIds()}); }); if (ENABLE_HTTP_API) { app.listen(HTTP_API_PORT, HTTP_API_ADDR, () => { console.log(`HTTP API bound to http://${HTTP_API_ADDR}:${HTTP_API_PORT}`); }); } await bindPublish(); await bindReply(); runDeltas(); runRequestHandlers(); await new Promise((resolve) => setTimeout(resolve, 200)); subscribeToSeeds(); await new Promise((resolve) => setTimeout(resolve, 200)); const users = new Users(); const taliesin = users.upsert({ id: 'taliesin-1', name: 'Taliesin', nameLong: 'Taliesin (Ladd)', age: Math.floor(Math.random() * 1000) }); taliesin.onUpdate((u: Entity) => { console.log('User updated', u); }); // TODO: Allow configuration regarding read/write concern i.e. // if we perform a read immediately do we see the value we wrote? // Intuition says yes, we want that-- but how do we expose the propagation status? const result = users.getOne(taliesin.id); const matches: boolean = JSON.stringify(result) === JSON.stringify(taliesin); console.log(`Result ${matches ? 'matches' : 'does not match'} expected.` + `\n\nExpected \n${JSON.stringify(taliesin)}` + `\nReceived\n${JSON.stringify(result)}`); })();