util: fix stylize of special properties in inspect

Previously, formatExtraProperties applied ctx.stylize to the entire
'[key]: value' string. This caused the colon and space to be styled,
making the output inconsistent with normal object properties.

Now, only the key itself is stylized, and the colon and space remain
unstyled, aligning with the formatting of regular properties.

Refs: #60131
PR-URL: #60479
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Ruben Bridgewater <[email protected]>
Reviewed-By: Jordan Harband <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>

Author: Snowflyt

lib/internal/util/inspect.js

@@ -2520,7 +2520,8 @@ function formatExtraProperties(ctx, value, recurseTimes, key, typedArray) {
   ctx.indentationLvl -= 2;
 
   // These entries are mainly getters. Should they be formatted like getters?
-  return ctx.stylize(`[${key}]: ${str}`, 'string');
+  const name = ctx.stylize(`[${key}]`, 'string');
+  return `${name}: ${str}`;
 }
 
 function formatProperty(ctx, value, recurseTimes, key, type, desc,

test/parallel/test-util-inspect.js

@@ -2391,6 +2391,20 @@ assert.strictEqual(
   inspect.styles.string = stringStyle;
 }
 
+// Special (extra) properties follow normal coloring:
+// only the name is colored, ":" and space are unstyled.
+{
+  const [open, close] = inspect.colors[inspect.styles.string];
+  const keyPattern = (k) => new RegExp(
+    `\\u001b\\[${open}m\\[${k}\\]\\u001b\\[${close}m: `
+  );
+  const colored = util.inspect(new Uint8Array(0), { showHidden: true, colors: true });
+  assert.match(colored, keyPattern('BYTES_PER_ELEMENT'));
+  assert.match(colored, keyPattern('length'));
+  assert.match(colored, keyPattern('byteLength'));
+  assert.match(colored, keyPattern('byteOffset'));
+}
+
 assert.strictEqual(
   inspect([1, 3, 2], { sorted: true }),
   inspect([1, 3, 2])