util: inspect boxed symbols like other primitives

Inspect boxed symbol objects in the same way other boxed primitives
are inspected.

Fixes: https://github.com/nodejs/node/issues/7639
PR-URL: https://github.com/nodejs/node/pull/7641
Reviewed-By: Michaël Zasso <mic.besace@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>

lib/util.js

@@ -314,6 +314,10 @@ function formatValue(ctx, value, recurseTimes) {
       formatted = formatPrimitiveNoColor(ctx, raw);
       return ctx.stylize('[String: ' + formatted + ']', 'string');
     }
+    if (typeof raw === 'symbol') {
+      formatted = formatPrimitiveNoColor(ctx, raw);
+      return ctx.stylize('[Symbol: ' + formatted + ']', 'symbol');
+    }
     if (typeof raw === 'number') {
       formatted = formatPrimitiveNoColor(ctx, raw);
       return ctx.stylize('[Number: ' + formatted + ']', 'number');

test/parallel/test-util-inspect.js

@@ -333,6 +333,7 @@ test_lines({
 
 // test boxed primitives output the correct values
 assert.equal(util.inspect(new String('test')), '[String: \'test\']');
+assert.equal(util.inspect(Object(Symbol('test'))), '[Symbol: Symbol(test)]');
 assert.equal(util.inspect(new Boolean(false)), '[Boolean: false]');
 assert.equal(util.inspect(new Boolean(true)), '[Boolean: true]');
 assert.equal(util.inspect(new Number(0)), '[Number: 0]');