Fix limit output missing braces

src/jupyter_contrib_nbextensions/nbextensions/limit_output/limit-output.yaml

@@ -15,4 +15,4 @@ Parameters:
 - name: limit_output_message
   description: Message to append when output is limited
   input_type: text
-  default: '<b>limit_output extension: Maximum message size exceeded</b>'
+  default: '<b>limit_output extension: Maximum message size of {limit_output_length} exceeded with {output_length} characters</b>'

src/jupyter_contrib_nbextensions/nbextensions/limit_output/main.js

@@ -19,7 +19,7 @@ define([
         // maximum number of characters the output area is allowed to print
         limit_output : 10000,
         // message to print when output is limited
-        limit_output_message : '<b>limit_output extension: Maximum message size exceeded</b>'
+        limit_output_message : '<b>limit_output extension: Maximum message size of {limit_output_length} exceeded with {output_length} characters</b>'
     };
 
     // to be called once config is loaded, this updates default config vals
@@ -47,20 +47,27 @@ define([
                         (msg.content.data['text/plain'] === undefined) ? 0 : String(msg.content.data['text/plain']).length,
                         (msg.content.data['text/html'] === undefined) ? 0 : String(msg.content.data['text/html']).length )
                 }
-                if (count > MAX_CHARACTERS)
-                    console.log("limit_output: output exceeded", MAX_CHARACTERS, "characters. Further output muted.");
+                if (count > MAX_CHARACTERS) {
+                    console.log("limit_output: output", count, "exceeded", MAX_CHARACTERS, "characters. Further output muted.");
                     if (msg.header.msg_type === "stream") {
                         msg.content.text = msg.content.text.substr(0, MAX_CHARACTERS)
                     } else {
-                        if (msg.content.data['text/plain'] !== undefined) msg.content.data['text/plain'] = msg.content.data['text/plain'].substr(0, MAX_CHARACTERS);
-                        if (msg.content.data['text/html'] !== undefined) msg.content.data['text/html'] = msg.content.data['text/html'].substr(0, MAX_CHARACTERS);
+                        if (msg.content.data['text/plain'] !== undefined) {
+                            msg.content.data['text/plain'] = msg.content.data['text/plain'].substr(0, MAX_CHARACTERS);
+                        }
+                        if (msg.content.data['text/html'] !== undefined) {
+                            msg.content.data['text/html'] = msg.content.data['text/html'].substr(0, MAX_CHARACTERS);
+                        }
                     }
                     var limitmsg = {};
                     limitmsg.data = [];
-                    limitmsg.data['text/html'] = params.limit_output_message;
+                    // allow simple substitutions for output length for quick debugging
+                    limitmsg.data['text/html'] = params.limit_output_message.replace("{limit_output_length}", MAX_CHARACTERS)
+                                                                            .replace("{output_length}", count);
                     this._handle_output(msg);
                     return this.append_display_data(limitmsg);
                 }
+            }
             return this._handle_output(msg);
         };
 

src/jupyter_contrib_nbextensions/nbextensions/limit_output/readme.md

@@ -25,3 +25,6 @@ Three types of messages are intercepted: `stream`, `execute_result`, `display_da
 For `stream`- type messages, the text string length is limited to `limit_output` number of characters
 For other message types, `text/plain` and `text/html` content length is counted` and if either
 exceeds `limit_output` charaters, will be truncated.
+
+The `limit_output_message` can be formatted to display the `limit_output` length and the current `output_length`,
+respectively using the replacement fields `{limit_output_length}` and `{output_length}`.