repl: use better uncaught exceptions indicator

This switches "Thrown:" with "Uncaught" to outline clearer that the
thrown error is not caught.

PR-URL: https://github.com/nodejs/node/pull/29676
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 21 insertions, 4 deletions

diff --git a/lib/repl.js b/lib/repl.js
index c1473588d3..55daf2f47f 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -552,11 +552,28 @@ function REPLServer(prompt,
       });
     } else {
       if (errStack === '') {
-        errStack = `Thrown: ${self.writer(e)}\n`;
-      } else {
-        const ln = errStack.endsWith('\n') ? '' : '\n';
-        errStack = `Thrown:\n${errStack}${ln}`;
+        errStack = self.writer(e);
+      }
+      const lines = errStack.split(/(?<=\n)/);
+      let matched = false;
+
+      errStack = '';
+      for (const line of lines) {
+        if (!matched && /^\[?([A-Z][a-z0-9_]*)*Error/.test(line)) {
+          errStack += writer.options.breakLength >= line.length ?
+            `Uncaught ${line}` :
+            `Uncaught:\n${line}`;
+          matched = true;
+        } else {
+          errStack += line;
+        }
+      }
+      if (!matched) {
+        const ln = lines.length === 1 ? ' ' : ':\n';
+        errStack = `Uncaught${ln}${errStack}`;
       }
+      // Normalize line endings.
+      errStack += errStack.endsWith('\n') ? '' : '\n';
       top.outputStream.write(errStack);
       top.clearBufferedCommand();
       top.lines.level = [];