cli: style node --help output with util.styleText

lib/internal/main/print_help.js

@@ -25,11 +25,16 @@ const {
 } = require('internal/process/pre_execution');
 
 const { getCLIOptionsInfo, getOptionValue } = require('internal/options');
+const { styleText } = require('util');
 
 const typeLookup = [];
 for (const key of ObjectKeys(types))
   typeLookup[types[key]] = key;
 
+function style(format, text) {
+  return styleText(format, text, { stream: process.stdout });
+}
+
 // Environment variables are parsed ad-hoc throughout the code base,
 // so we gather the documentation here.
 const { hasIntl, hasSmallICU, hasNodeOptions } = internalBinding('config');
@@ -117,7 +122,7 @@ function getArgDescription(type) {
 }
 
 function format(
-  { options, aliases = new SafeMap(), firstColumn, secondColumn },
+  { options, aliases = new SafeMap(), firstColumn, secondColumn, nameStyle = [] },
 ) {
   let text = '';
   let maxFirstColumnUsed = 0;
@@ -176,7 +181,7 @@ function format(
       displayHelpText += ' (currently set)';
     }
 
-    text += displayName;
+    text += style(nameStyle, displayName);
     maxFirstColumnUsed = MathMax(maxFirstColumnUsed, displayName.length);
     if (displayName.length >= firstColumn)
       text += '\n' + StringPrototypeRepeat(' ', firstColumn);
@@ -194,6 +199,7 @@ function format(
       aliases,
       firstColumn: maxFirstColumnUsed + 2,
       secondColumn,
+      nameStyle,
     });
   }
 
@@ -214,20 +220,29 @@ function print(stream) {
                                'interactive mode if a tty)' });
   options.set('--', { helpText: 'indicate the end of node options' });
   let helpText = (
-    'Usage: node [options] [ script.js ] [arguments]\n' +
-    '       node inspect [options] [ script.js | host:port ] [arguments]\n\n' +
-    'Options:\n');
+    style('bold',
+          'Usage: node [options] [ script.js ] [arguments]\n' +
+      '       node inspect [options] [ script.js | host:port ] [arguments]') +
+    '\n\n' + style('bold', 'Options:') + '\n');
   helpText += (indent(format({
-    options, aliases, firstColumn, secondColumn,
+    options, aliases, firstColumn, secondColumn, nameStyle: ['bold', 'green'],
   }), 2));
 
-  helpText += ('\nEnvironment variables:\n');
+  helpText += ('\n' + style('bold', 'Environment variables:') + '\n');
 
   helpText += (format({
-    options: envVars, firstColumn, secondColumn,
+    options: envVars, firstColumn, secondColumn, nameStyle: ['bold', 'magenta'],
   }));
 
-  helpText += ('\nDocumentation can be found at https://nodejs.org/');
+  helpText += ('\nDocumentation can be found at ' +
+    style(['blue', 'underline'], 'https://nodejs.org/'));
+
+  helpText = RegExpPrototypeSymbolReplace(
+    / \(currently set\)/g,
+    helpText,
+    style('dim', ' (currently set)'),
+  );
+
   console.log(helpText);
 }
 

test/parallel/test-cli-node-print-help-style.js

@@ -0,0 +1,64 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const { execFile } = require('child_process');
+
+// eslint-disable-next-line no-control-regex
+const ANSI_SGR_REGEX = new RegExp('\x1b\\[[0-9;]*m', 'g');
+
+function stripAnsi(text) {
+  return text.replace(ANSI_SGR_REGEX, '');
+}
+
+// Test: FORCE_COLOR=1 produces styled output
+{
+  const env = { ...process.env, FORCE_COLOR: '1' };
+  execFile(process.execPath, ['--help'], { env },
+           common.mustSucceed((stdout) => {
+             assert.ok(stdout.includes('\x1b[1m'), 'bold for headers should be present');
+             assert.ok(stdout.includes('\x1b[32m'), 'green for option names should be present');
+             assert.ok(stdout.includes('\x1b[35m'), 'magenta for env var names should be present');
+             assert.ok(stdout.includes('\x1b[34m'), 'blue for URL should be present');
+             assert.ok(stdout.includes('\x1b[4m'), 'underline for URL should be present');
+           }));
+}
+
+// Test: NO_COLOR=1 produces plain output
+{
+  const env = { ...process.env, NO_COLOR: '1' };
+  delete env.FORCE_COLOR;
+  execFile(process.execPath, ['--help'], { env },
+           common.mustSucceed((stdout) => {
+             assert.ok(stripAnsi(stdout) === stdout,
+                       'no ANSI escape sequences should be present with NO_COLOR=1');
+           }));
+}
+
+// Test: piped (non-TTY, no FORCE_COLOR) produces plain output
+{
+  const env = { ...process.env };
+  delete env.FORCE_COLOR;
+  delete env.NO_COLOR;
+  delete env.NODE_DISABLE_COLORS;
+  execFile(process.execPath, ['--help'], { env },
+           common.mustSucceed((stdout) => {
+             assert.ok(stripAnsi(stdout) === stdout,
+                       'no ANSI escape sequences should be present when piped (non-TTY)');
+           }));
+}
+
+// Test: alignment preservation - stripped styled output matches plain output
+{
+  const envStyled = { ...process.env, FORCE_COLOR: '1' };
+  const envPlain = { ...process.env, NO_COLOR: '1' };
+  delete envPlain.FORCE_COLOR;
+  execFile(process.execPath, ['--help'], { env: envStyled },
+           common.mustSucceed((styledStdout) => {
+             execFile(process.execPath, ['--help'], { env: envPlain },
+                      common.mustSucceed((plainStdout) => {
+                        assert.ok(stripAnsi(styledStdout) === plainStdout,
+                                  'stripped styled output should match plain output (alignment preservation)');
+                      }));
+           }));
+}