Make Mermaid.js limit configurable (#16519)

* Make Mermaid.js limit configurable

Add `MERMAID_MAX_SOURCE_CHARACTERS` to `[markup]` settings
to make the maximum size of a mermaid render configurable.

Fix #16513

Signed-off-by: Andrew Thornton <art27@cantab.net>

* fixup! Make Mermaid.js limit configurable

* Update custom/conf/app.example.ini

Co-authored-by: silverwind <me@silverwind.io>

* Update docs/content/doc/advanced/config-cheat-sheet.en-us.md

Co-authored-by: silverwind <me@silverwind.io>

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/web_src/js/markup/mermaid.js b/web_src/js/markup/mermaid.js
index d0aefd1aff..a5bd0e235c 100644
--- a/web_src/js/markup/mermaid.js
+++ b/web_src/js/markup/mermaid.js
@@ -1,4 +1,4 @@
-const MAX_SOURCE_CHARACTERS = 5000;
+const {MermaidMaxSourceCharacters} = window.config;
 
 function displayError(el, err) {
   el.closest('pre').classList.remove('is-loading');
@@ -26,8 +26,8 @@ export async function renderMermaid(els) {
   });
 
   for (const el of els) {
-    if (el.textContent.length > MAX_SOURCE_CHARACTERS) {
-      displayError(el, new Error(`Mermaid source of ${el.textContent.length} characters exceeds the maximum allowed length of ${MAX_SOURCE_CHARACTERS}.`));
+    if (MermaidMaxSourceCharacters >= 0 && el.textContent.length > MermaidMaxSourceCharacters) {
+      displayError(el, new Error(`Mermaid source of ${el.textContent.length} characters exceeds the maximum allowed length of ${MermaidMaxSourceCharacters}.`));
       continue;
     }