diff --git a/src/hyper/render.clj b/src/hyper/render.clj
index 20ace83..09d1ea2 100644
--- a/src/hyper/render.clj
+++ b/src/hyper/render.clj
@@ -2,7 +2,8 @@
"Rendering pipeline.
Handles rendering hiccup to HTML and formatting Datastar SSE events."
- (:require [dev.onionpancakes.chassis.core :as c]
+ (:require [clojure.string :as string]
+ [dev.onionpancakes.chassis.core :as c]
[hyper.context :as context]
[hyper.routes :as routes]
[hyper.state :as state]
@@ -27,10 +28,16 @@
event: datastar-patch-elements
data: elements
- (blank line to end event)"
+ For multi-line HTML content, emits multiple 'data: elements' lines
+ that Datastar will concatenate. This prevents \n in HTML from
+ prematurely terminating the SSE event."
[html]
- (str "event: datastar-patch-elements\n"
- "data: elements " html "\n\n"))
+ (let [lines (string/split-lines html)]
+ (str "event: datastar-patch-elements\n"
+ (->> lines
+ (map (fn [line] (str "data: elements " line "\n")))
+ (apply str))
+ "\n")))
(defn mark-head-elements
"Add `{:data-hyper-head true}` to each top-level hiccup element in a
diff --git a/test/hyper/e2e_test.clj b/test/hyper/e2e_test.clj
index ba4495c..0f7b4d8 100644
--- a/test/hyper/e2e_test.clj
+++ b/test/hyper/e2e_test.clj
@@ -578,8 +578,22 @@
(is (= "Live Reloaded!" (w/text-content "h1")))
(is (= "This content was hot-swapped"
- (w/text-content "#reloaded-marker")))))
+ (w/text-content "#reloaded-marker"))))
+ ;; Test that content with newlines renders correctly
+ (testing "Content with newlines preserved in route handler"
+ (alter-var-root #'*test-routes*
+ (constantly
+ [["/" {:name :home
+ :title "Newlines Test"
+ :get (fn [_]
+ [:div
+ [:textarea#newline-content "line1\nline2"]
+ [:pre#pre-content "code\nwith\n\nnew\n\nlines\n\n"]])}]]))
+ (w/navigate (str base-url "/"))
+ (wait-for-sse)
+ (is (= "line1\nline2" (w/text-content "#newline-content")))
+ (is (= "code\nwith\n\nnew\n\nlines\n\n" (w/text-content "#pre-content")))))
(finally
(close-browser! browser-info)))))
diff --git a/test/hyper/render_test.clj b/test/hyper/render_test.clj
index ff33f4c..30f40cd 100644
--- a/test/hyper/render_test.clj
+++ b/test/hyper/render_test.clj
@@ -38,7 +38,24 @@
(let [html "test"
fragment (render/format-datastar-fragment html)]
(is (.contains fragment html))
- (is (.startsWith fragment "event: datastar-patch-elements\n")))))
+ (is (.startsWith fragment "event: datastar-patch-elements\n"))))
+
+ (testing "HTML with 2 newlines emits multiple data lines"
+ (let [html "code\nwith\nnewline
"
+ fragment (render/format-datastar-fragment html)]
+ (is (= 3 (count (re-seq #"data: elements" fragment))))
+ (is (.contains fragment "code"))
+ (is (.contains fragment "with"))
+ (is (.contains fragment "newline
"))
+ (is (.endsWith fragment "\n\n"))))
+
+ (testing "HTML with double newlines emits multiple data lines"
+ (let [html ""
+ fragment (render/format-datastar-fragment html)]
+ (is (= 3 (count (re-seq #"data: elements" fragment))))
+ (is (.contains fragment ""))
+ (is (.endsWith fragment "\n\n")))))
(deftest test-render-tab
(testing "render-tab returns nil when no render-fn is registered"