tty: truecolor check moved before 256 check

256 color would be return instead of 16m if both env variables were set

* tty: improve color check order highest spec first
* tty: add test for TERM and COLORTERM set
* tty: move COLORTERM check outside TERM closure
* tty: remove extra if check for COLORTERM

Refs: https://github.com/nodejs/node/issues/27609

PR-URL: https://github.com/nodejs/node/pull/30474
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/lib/internal/tty.js b/lib/internal/tty.js
index faf5df9b42..98975fa68a 100644
--- a/lib/internal/tty.js
+++ b/lib/internal/tty.js
@@ -173,6 +173,10 @@ function getColorDepth(env = process.env) {
       return COLORS_256;
   }
 
+  if (env.COLORTERM === 'truecolor' || env.COLORTERM === '24bit') {
+    return COLORS_16m;
+  }
+
   if (env.TERM) {
     if (/^xterm-256/.test(env.TERM))
       return COLORS_256;
@@ -188,13 +192,10 @@ function getColorDepth(env = process.env) {
       }
     }
   }
-
+  // Move 16 color COLORTERM below 16m and 256
   if (env.COLORTERM) {
-    if (env.COLORTERM === 'truecolor' || env.COLORTERM === '24bit')
-      return COLORS_16m;
     return COLORS_16;
   }
-
   return COLORS_2;
 }