console: implement minimal `console.group()`

Node.js exposes `console.group()` and `console.groupEnd()` via the
inspector. These functions have no apparent effect when called from
Node.js without the inspector. We cannot easily hide them when Node.js
is started without the inspector because we support opening the
inspector during runtime via `inspector.port()`.

Implement a minimal `console.group()`/`console.groupEnd()`. More
sophisticated implementations are possible, but they can be done in
userland and/or features can be added to this at a later time.

`console.groupCollapsed()` is implemented as an alias for
`console.group()`.

PR-URL: https://github.com/nodejs/node/pull/14910
Fixes: https://github.com/nodejs/node/issues/1716
Ref: https://github.com/nodejs/node/issues/12675
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

1 files changed, 111 insertions, 0 deletions

diff --git a/test/parallel/test-console-group.js b/test/parallel/test-console-group.js
new file mode 100644
index 0000000000..8f7d84f2f1
--- /dev/null
+++ b/test/parallel/test-console-group.js
@@ -0,0 +1,111 @@
+'use strict';
+const common = require('../common');
+
+const assert = require('assert');
+const Console = require('console').Console;
+
+let c, stdout, stderr;
+
+function setup() {
+  stdout = '';
+  common.hijackStdout(function(data) {
+    stdout += data;
+  });
+
+  stderr = '';
+  common.hijackStderr(function(data) {
+    stderr += data;
+  });
+
+  c = new Console(process.stdout, process.stderr);
+}
+
+function teardown() {
+  common.restoreStdout();
+  common.restoreStderr();
+}
+
+// Basic group() functionality
+{
+  setup();
+  const expectedOut = 'This is the outer level\n' +
+                      '  Level 2\n' +
+                      '    Level 3\n' +
+                      '  Back to level 2\n' +
+                      'Back to the outer level\n' +
+                      'Still at the outer level\n';
+
+
+  const expectedErr = '    More of level 3\n';
+
+  c.log('This is the outer level');
+  c.group();
+  c.log('Level 2');
+  c.group();
+  c.log('Level 3');
+  c.warn('More of level 3');
+  c.groupEnd();
+  c.log('Back to level 2');
+  c.groupEnd();
+  c.log('Back to the outer level');
+  c.groupEnd();
+  c.log('Still at the outer level');
+
+  assert.strictEqual(stdout, expectedOut);
+  assert.strictEqual(stderr, expectedErr);
+  teardown();
+}
+
+// Group indentation is tracked per Console instance.
+{
+  setup();
+  const expectedOut = 'No indentation\n' +
+                      'None here either\n' +
+                      '  Now the first console is indenting\n' +
+                      'But the second one does not\n';
+  const expectedErr = '';
+
+  const c2 = new Console(process.stdout, process.stderr);
+  c.log('No indentation');
+  c2.log('None here either');
+  c.group();
+  c.log('Now the first console is indenting');
+  c2.log('But the second one does not');
+
+  assert.strictEqual(stdout, expectedOut);
+  assert.strictEqual(stderr, expectedErr);
+  teardown();
+}
+
+// Make sure labels work.
+{
+  setup();
+  const expectedOut = 'This is a label\n' +
+                      '  And this is the data for that label\n';
+  const expectedErr = '';
+
+  c.group('This is a label');
+  c.log('And this is the data for that label');
+
+  assert.strictEqual(stdout, expectedOut);
+  assert.strictEqual(stderr, expectedErr);
+  teardown();
+}
+
+// Check that console.groupCollapsed() is an alias of console.group()
+{
+  setup();
+  const expectedOut = 'Label\n' +
+                      '  Level 2\n' +
+                      '    Level 3\n';
+  const expectedErr = '';
+
+  c.groupCollapsed('Label');
+  c.log('Level 2');
+  c.groupCollapsed();
+  c.log('Level 3');
+
+  assert.strictEqual(stdout, expectedOut);
+  assert.strictEqual(stderr, expectedErr);
+  teardown();
+}