console: skip/strip %c formatting

Fixes: #29605
Refs: https://console.spec.whatwg.org
PR-URL: #29606
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

doc/api/util.md

@@ -185,6 +185,9 @@ property take precedence over `--trace-deprecation` and
 <!-- YAML
 added: v0.5.3
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/29606
+    description: The `%c` specifier is ignored now.
   - version: v11.4.0
     pr-url: https://github.com/nodejs/node/pull/23708
     description: The `%d`, `%f` and `%i` specifiers now support Symbols
@@ -240,6 +243,8 @@ corresponding argument. Supported specifiers are:
 * `%O` - `Object`. A string representation of an object with generic JavaScript
   object formatting. Similar to `util.inspect()` without options. This will show
   the full object not including non-enumerable properties and proxies.
+* `%c` - `CSS`. This specifier is currently ignored, and will skip any CSS
+  passed in.
 * `%%` - single percent sign (`'%'`). This does not consume an argument.
 * Returns: {string} The formatted string
 

lib/internal/util/inspect.js

@@ -1596,15 +1596,13 @@ function formatWithOptions(inspectOptions, ...args) {
               tempStr = inspect(args[++a], inspectOptions);
               break;
             case 111: // 'o'
-            {
               tempStr = inspect(args[++a], {
                 ...inspectOptions,
                 showHidden: true,
                 showProxy: true,
                 depth: 4
               });
               break;
-            }
             case 105: // 'i'
               const tempInteger = args[++a];
               if (typeof tempInteger === 'bigint') {
@@ -1623,6 +1621,10 @@ function formatWithOptions(inspectOptions, ...args) {
                 tempStr = formatNumber(stylizeNoColor, parseFloat(tempFloat));
               }
               break;
+            case 99: // 'c'
+              a += 1;
+              tempStr = '';
+              break;
             case 37: // '%'
               str += first.slice(lastPos, i);
               lastPos = i + 1;

test/parallel/test-util-format.js

@@ -317,6 +317,12 @@ assert.strictEqual(util.format('abc%', 1), 'abc% 1');
 assert.strictEqual(util.format('%i', 1, 'number'), '1 number');
 assert.strictEqual(util.format('%i', 1, () => {}), '1 [Function]');
 
+// %c from https://console.spec.whatwg.org/
+assert.strictEqual(util.format('%c'), '%c');
+assert.strictEqual(util.format('%cab'), '%cab');
+assert.strictEqual(util.format('%cab', 'color: blue'), 'ab');
+assert.strictEqual(util.format('%cab', 'color: blue', 'c'), 'ab c');
+
 {
   const o = {};
   o.o = o;