🔧 fix: #1369 don't block microtask queue in SSE

Author: SaltyAom

CHANGELOG.md

@@ -1,3 +1,11 @@
+# 1.3.21 - 31 Aug 2025
+Bug fix:
+- [#1356](https://github.com/elysiajs/elysia/pull/1356) webSocket validation error handling in BunAdapter
+- [#1358](https://github.com/elysiajs/elysia/pull/1358) allow overriding websocket handler with listen options
+- [#1365](https://github.com/elysiajs/elysia/pull/1365) check if the plugin.constructor (fix import module in Bun 1.2.21)
+- [#1367](https://github.com/elysiajs/elysia/pull/1367) .trace hooks (onAfterResponse, etc...) not being called
+- [#1369](https://github.com/elysiajs/elysia/issues/1369) don't block microtask queue in SSE
+
 # 1.3.20 - 24 Aug 2025
 Change:
 - mime is undefined when using `Elysia.file` in Web Standard Adapter

example/a.ts

@@ -1,10 +1,15 @@
-import { Elysia, sse, t } from '../src'
-import { req } from '../test/utils'
+import { Elysia } from '../src'
+
+const plugin1 = new Elysia().derive({ as: 'scoped' }, () => ({
+	hello: 'world'
+}))
+
+const plugin2 = new Elysia()
+	.use(plugin1)
+	.derive({ as: 'scoped' }, ({ hello }) => ({ hello }))
 
 const app = new Elysia()
-	.get('/', function* () {
-		yield sse('a')
-		yield sse('b')
-	})
-	.get('/proxy', () => app.handle(new Request('http://localhost')))
+	.use(plugin2)
+	// This is undefined
+	.get('/', ({ hello }) => typeof hello)
 	.listen(3000)

package.json

@@ -1,7 +1,7 @@
 {
 	"name": "elysia",
 	"description": "Ergonomic Framework for Human",
-	"version": "1.3.20",
+	"version": "1.3.21",
 	"author": {
 		"name": "saltyAom",
 		"url": "https://github.com/SaltyAom",

src/adapter/utils.ts

@@ -247,24 +247,34 @@ export const createStreamHandler =
 							if (chunk === undefined || chunk === null) continue
 
 							// @ts-ignore
-							if (chunk.toSSE)
+							if (chunk.toSSE) {
 								// @ts-ignore
 								controller.enqueue(chunk.toSSE())
-							else if (typeof chunk === 'object')
-								try {
-									controller.enqueue(
-										format(JSON.stringify(chunk))
-									)
-								} catch {
+							} else {
+								if (typeof chunk === 'object')
+									try {
+										controller.enqueue(
+											format(JSON.stringify(chunk))
+										)
+									} catch {
+										controller.enqueue(
+											format(chunk.toString())
+										)
+									}
+								else
 									controller.enqueue(format(chunk.toString()))
-								}
-							else controller.enqueue(format(chunk.toString()))
-
-							// Wait for the next event loop
-							// Otherwise the data will be mixed up
-							await new Promise<void>((resolve) =>
-								setTimeout(() => resolve(), 0)
-							)
+
+								if (!isSSE)
+									/**
+									 * Wait for the next event loop
+									 * otherwise the data will be mixed up
+									 *
+									 * @see https://github.com/elysiajs/elysia/issues/741
+									 */
+									await new Promise<void>((resolve) =>
+										setTimeout(() => resolve(), 0)
+									)
+							}
 						}
 					} catch (error) {
 						console.warn(error)
@@ -357,7 +367,6 @@ export const createResponseHandler = (handler: CreateHandlerParameter) => {
 					status: set.status as number
 				})
 
-
 				if (
 					!(newResponse as Response).headers.has('content-length') &&
 					(newResponse as Response).headers.get(

src/compose.ts

@@ -907,7 +907,7 @@ export const composeHandler = ({
 				endUnit()
 			}
 		}
-		
+
 		reporter.resolve()
 
 		afterResponse += '})\n'
@@ -1678,6 +1678,8 @@ export const composeHandler = ({
 							mapResponse('resolved') +
 							`}` +
 							`else Object.assign(c, resolved)\n`
+
+					endUnit()
 				} else if (!returning) {
 					fnLiteral += isAsync(beforeHandle)
 						? `await e.beforeHandle[${i}](c)\n`
@@ -2517,7 +2519,7 @@ export const composeErrorHandler = (app: AnyElysia) => {
 			total: hooks.afterResponse?.length,
 			name: 'context'
 		})
-		
+
 		if (hooks.afterResponse?.length && hooks.afterResponse) {
 			for (let i = 0; i < hooks.afterResponse.length; i++) {
 				const fn = hooks.afterResponse[i].fn