util: change items unknown style

We mainly use <> to visualize special information that is not
directly visible as property.

PR-URL: #20792
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>

lib/util.js

@@ -610,14 +610,14 @@ function formatValue(ctx, value, recurseTimes, ln) {
       if (ctx.showHidden) {
         formatter = formatWeakSet;
       } else {
-        extra = '[items unknown]';
+        extra = '<items unknown>';
       }
     } else if (isWeakMap(value)) {
       braces[0] = `${getPrefix(constructor, tag)}{`;
       if (ctx.showHidden) {
         formatter = formatWeakMap;
       } else {
-        extra = '[items unknown]';
+        extra = '<items unknown>';
       }
     } else if (types.isModuleNamespaceObject(value)) {
       braces[0] = `[${tag}] {`;

test/parallel/test-util-inspect.js

@@ -1310,7 +1310,7 @@ util.inspect(process);
   assert.strictEqual(out, expect);
 
   out = util.inspect(weakMap);
-  expect = 'WeakMap { [items unknown] }';
+  expect = 'WeakMap { <items unknown> }';
   assert.strictEqual(out, expect);
 
   out = util.inspect(weakMap, { maxArrayLength: 0, showHidden: true });
@@ -1334,7 +1334,7 @@ util.inspect(process);
   assert.strictEqual(out, expect);
 
   out = util.inspect(weakSet);
-  expect = 'WeakSet { [items unknown] }';
+  expect = 'WeakSet { <items unknown> }';
   assert.strictEqual(out, expect);
 
   out = util.inspect(weakSet, { maxArrayLength: -2, showHidden: true });