From 82d32ee761913c531698c8340aa0d91d0708f23e Mon Sep 17 00:00:00 2001
From: Michael Howell <michael@notriddle.com>
Date: Wed, 7 Jul 2021 10:44:51 -0700
Subject: [PATCH] feat(playground): show "No output" on playgrounds that print
 nothing

Fixes #1594
---
 src/theme/book.js         | 10 +++++++++-
 src/theme/css/general.css |  4 ++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/theme/book.js b/src/theme/book.js
index 5e386369..24ed97d0 100644
--- a/src/theme/book.js
+++ b/src/theme/book.js
@@ -133,7 +133,15 @@ function playground_text(playground) {
             body: JSON.stringify(params)
         })
         .then(response => response.json())
-        .then(response => result_block.innerText = response.result)
+        .then(response => {
+            if (response.result.trim() === '') {
+                result_block.innerText = "No output";
+                result_block.classList.add("result-no-output");
+            } else {
+                result_block.innerText = response.result;
+                result_block.classList.remove("result-no-output");
+            }
+        })
         .catch(error => result_block.innerText = "Playground Communication: " + error.message);
     }
 
diff --git a/src/theme/css/general.css b/src/theme/css/general.css
index 2cf347f9..63317b39 100644
--- a/src/theme/css/general.css
+++ b/src/theme/css/general.css
@@ -175,3 +175,7 @@ blockquote {
     margin: 5px 0px;
     font-weight: bold;
 }
+
+.result-no-output {
+    font-style: italic;
+}