added Server Side Events

fixtures/db.json

@@ -1,11 +1,25 @@
 {
   "posts": [
-    { "id": "1", "title": "a title" },
-    { "id": "2", "title": "another title" }
+    {
+      "id": "1",
+      "title": "a title"
+    },
+    {
+      "id": "2",
+      "title": "another title"
+    }
   ],
   "comments": [
-    { "id": "1", "text": "a comment about post 1", "postId": "1" },
-    { "id": "2", "text": "another comment about post 1", "postId": "1" }
+    {
+      "id": "1",
+      "text": "a comment about post 1",
+      "postId": "1"
+    },
+    {
+      "id": "2",
+      "text": "another comment about post 1",
+      "postId": "1"
+    }
   ],
   "profile": {
     "name": "typicode"

package.json

@@ -57,6 +57,7 @@
     "json5": "^2.2.3",
     "lowdb": "^7.0.1",
     "milliparsec": "^4.0.0",
+    "rxjs": "^7.8.1",
     "sirv": "^2.0.4",
     "sort-on": "^6.1.0"
   }

src/app.ts

@@ -8,6 +8,8 @@ import { Low } from 'lowdb'
 import { json } from 'milliparsec'
 import sirv from 'sirv'
 
+import { Subject } from 'rxjs'
+
 import { Data, isItem, Service } from './service.js'
 
 const __dirname = dirname(fileURLToPath(import.meta.url))
@@ -30,6 +32,8 @@ export function createApp(db: Low<Data>, options: AppOptions = {}) {
   // Create app
   const app = new App()
 
+  const event$ = new Subject<object>();
+
   // Static files
   app.use(sirv('public', { dev: !isProduction }))
   options.static
@@ -55,6 +59,20 @@ export function createApp(db: Low<Data>, options: AppOptions = {}) {
     res.send(eta.render('index.html', { data: db.data })),
   )
 
+  app.get('/events', (_req, res) => {
+    res.header('Content-Type', 'text/event-stream');
+
+    event$.subscribe({
+      next: (data) => {
+        res.write(`data: ${JSON.stringify(data)}\n\n`);
+        res.flushHeaders();
+      },
+      complete: () => {
+        res.end();
+      },
+    });
+  })
+
   app.get('/:name', (req, res, next) => {
     const { name = '' } = req.params
     const query = Object.fromEntries(
@@ -86,6 +104,12 @@ export function createApp(db: Low<Data>, options: AppOptions = {}) {
     if (isItem(req.body)) {
       res.locals['data'] = await service.create(name, req.body)
     }
+    event$.next(
+      { 
+        type: "post", 
+        params: req.params
+      }
+    );
     next?.()
   })
 
@@ -94,6 +118,12 @@ export function createApp(db: Low<Data>, options: AppOptions = {}) {
     if (isItem(req.body)) {
       res.locals['data'] = await service.update(name, req.body)
     }
+    event$.next(
+      { 
+        type: "put", 
+        params: req.params
+      }
+    );
     next?.()
   })
 
@@ -102,6 +132,12 @@ export function createApp(db: Low<Data>, options: AppOptions = {}) {
     if (isItem(req.body)) {
       res.locals['data'] = await service.updateById(name, id, req.body)
     }
+    event$.next(
+      { 
+        type: "put", 
+        params: req.params
+      }
+    );
     next?.()
   })
 
@@ -110,6 +146,12 @@ export function createApp(db: Low<Data>, options: AppOptions = {}) {
     if (isItem(req.body)) {
       res.locals['data'] = await service.patch(name, req.body)
     }
+    event$.next(
+      { 
+        type: "patch", 
+        params: req.params
+      }
+    );
     next?.()
   })
 
@@ -118,6 +160,12 @@ export function createApp(db: Low<Data>, options: AppOptions = {}) {
     if (isItem(req.body)) {
       res.locals['data'] = await service.patchById(name, id, req.body)
     }
+    event$.next(
+      { 
+        type: "patch", 
+        params: req.params
+      }
+    );
     next?.()
   })
 
@@ -128,6 +176,12 @@ export function createApp(db: Low<Data>, options: AppOptions = {}) {
       id,
       req.query['_dependent'],
     )
+    event$.next(
+      { 
+        type: "delete", 
+        params: req.params
+      }
+    );
     next?.()
   })