tools: enable additional eslint rules

Enable additional rules that node either already adheres to
or it makes sense to do so going forward: for-direction,
accessor-pairs, no-lonely-if and symbol-description.

Fix all instances of no-lonely-if in lib & test and disable
accessor-pairs in test-util-inspect.

PR-URL: https://github.com/nodejs/node/pull/16243
Refs: https://eslint.org/docs/rules/for-direction
Refs: https://eslint.org/docs/rules/accessor-pairs
Refs: https://eslint.org/docs/rules/no-lonely-if
Refs: https://eslint.org/docs/rules/symbol-description
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/lib/_http_incoming.js b/lib/_http_incoming.js
index 6e5aff1cc9..696fcc3b4c 100644
--- a/lib/_http_incoming.js
+++ b/lib/_http_incoming.js
@@ -301,10 +301,9 @@ function _addHeaderLine(field, value, dest) {
     } else {
       dest['set-cookie'] = [value];
     }
-  } else {
+  } else if (dest[field] === undefined) {
     // Drop duplicates
-    if (dest[field] === undefined)
-      dest[field] = value;
+    dest[field] = value;
   }
 }