util: add util.inspect compact option

The current default formatting is not ideal and this improves
the situation by formatting the output more intuitiv.

1) All object keys are now indented by 2 characters instead of
   sometimes 2 and sometimes 3 characters.
2) Each object key will now use an individual line instead of
   sharing a line potentially with multiple object keys.
3) Long strings will now be split into multiple lines in case
   they exceed the "lineBreak" option length (including the
   current indentation).
4) Opening braces are now directly behind a object property
   instead of using a new line.
5) Switch inspect "base" order. In case the compact option is set
   to `false`, inspect will now print
     "[Function: foo] {\n  property: 'data'\n}"
   instead of
     "{ [Function: foo]\n  property: 'data'\n}".

PR-URL: https://github.com/nodejs/node/pull/17576
Reviewed-By: Anna Henningsen <anna@addaleax.net>

1 files changed, 137 insertions, 0 deletions

diff --git a/test/parallel/test-util-inspect.js b/test/parallel/test-util-inspect.js
index 0cc603d91f..335ba09bd7 100644
--- a/test/parallel/test-util-inspect.js
+++ b/test/parallel/test-util-inspect.js
@@ -1213,3 +1213,140 @@ assert.doesNotThrow(() => util.inspect(process));
   assert.strictEqual(util.inspect(new NotStringClass()),
                      'NotStringClass {}');
 }
+
+{
+  const o = {
+    a: [1, 2, [[
+      'Lorem ipsum dolor\nsit amet,\tconsectetur adipiscing elit, sed do ' +
+        'eiusmod tempor incididunt ut labore et dolore magna aliqua.',
+      'test',
+      'foo']], 4],
+    b: new Map([['za', 1], ['zb', 'test']])
+  };
+
+  let out = util.inspect(o, { compact: true, depth: 5, breakLength: 80 });
+  let expect = [
+    '{ a: ',
+    '   [ 1,',
+    '     2,',
+    "     [ [ 'Lorem ipsum dolor\\nsit amet,\\tconsectetur adipiscing elit, " +
+      "sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.',",
+    "         'test',",
+    "         'foo' ] ],",
+    '     4 ],',
+    "  b: Map { 'za' => 1, 'zb' => 'test' } }",
+  ].join('\n');
+  assert.strictEqual(out, expect);
+
+  out = util.inspect(o, { compact: false, depth: 5, breakLength: 60 });
+  expect = [
+    '{',
+    '  a: [',
+    '    1,',
+    '    2,',
+    '    [',
+    '      [',
+    '        \'Lorem ipsum dolor\\nsit amet,\\tconsectetur \' +',
+    '          \'adipiscing elit, sed do eiusmod tempor \' +',
+    '          \'incididunt ut labore et dolore magna \' +',
+    '          \'aliqua.\',',
+    '        \'test\',',
+    '        \'foo\'',
+    '      ]',
+    '    ],',
+    '    4',
+    '  ],',
+    '  b: Map {',
+    '    \'za\' => 1,',
+    '    \'zb\' => \'test\'',
+    '  }',
+    '}'
+  ].join('\n');
+  assert.strictEqual(out, expect);
+
+  out = util.inspect(o.a[2][0][0], { compact: false, breakLength: 30 });
+  expect = [
+    '\'Lorem ipsum dolor\\nsit \' +',
+    '  \'amet,\\tconsectetur \' +',
+    '  \'adipiscing elit, sed do \' +',
+    '  \'eiusmod tempor incididunt \' +',
+    '  \'ut labore et dolore magna \' +',
+    '  \'aliqua.\''
+  ].join('\n');
+  assert.strictEqual(out, expect);
+
+  out = util.inspect(
+    '12345678901234567890123456789012345678901234567890',
+    { compact: false, breakLength: 3 });
+  expect = '\'12345678901234567890123456789012345678901234567890\'';
+  assert.strictEqual(out, expect);
+
+  out = util.inspect(
+    '12 45 78 01 34 67 90 23 56 89 123456789012345678901234567890',
+    { compact: false, breakLength: 3 });
+  expect = [
+    '\'12 45 78 01 34 \' +',
+    '  \'67 90 23 56 89 \' +',
+    '  \'123456789012345678901234567890\''
+  ].join('\n');
+  assert.strictEqual(out, expect);
+
+  out = util.inspect(
+    '12 45 78 01 34 67 90 23 56 89 1234567890123 0',
+    { compact: false, breakLength: 3 });
+  expect = [
+    '\'12 45 78 01 34 \' +',
+    '  \'67 90 23 56 89 \' +',
+    '  \'1234567890123 0\''
+  ].join('\n');
+  assert.strictEqual(out, expect);
+
+  out = util.inspect(
+    '12 45 78 01 34 67 90 23 56 89 12345678901234567 0',
+    { compact: false, breakLength: 3 });
+  expect = [
+    '\'12 45 78 01 34 \' +',
+    '  \'67 90 23 56 89 \' +',
+    '  \'12345678901234567 \' +',
+    '  \'0\''
+  ].join('\n');
+  assert.strictEqual(out, expect);
+
+  o.a = () => {};
+  o.b = new Number(3);
+  out = util.inspect(o, { compact: false, breakLength: 3 });
+  expect = [
+    '{',
+    '  a: [Function],',
+    '  b: [Number: 3]',
+    '}'
+  ].join('\n');
+  assert.strictEqual(out, expect);
+
+  out = util.inspect(o, { compact: false, breakLength: 3, showHidden: true });
+  expect = [
+    '{',
+    '  a: [Function] {',
+    '    [length]: 0,',
+    "    [name]: ''",
+    '  },',
+    '  b: [Number: 3]',
+    '}'
+  ].join('\n');
+  assert.strictEqual(out, expect);
+
+  o[util.inspect.custom] = () => 42;
+  out = util.inspect(o, { compact: false, breakLength: 3 });
+  expect = '42';
+  assert.strictEqual(out, expect);
+
+  o[util.inspect.custom] = () => '12 45 78 01 34 67 90 23';
+  out = util.inspect(o, { compact: false, breakLength: 3 });
+  expect = '12 45 78 01 34 67 90 23';
+  assert.strictEqual(out, expect);
+
+  o[util.inspect.custom] = () => ({ a: '12 45 78 01 34 67 90 23' });
+  out = util.inspect(o, { compact: false, breakLength: 3 });
+  expect = '{\n  a: \'12 45 78 01 34 \' +\n    \'67 90 23\'\n}';
+  assert.strictEqual(out, expect);
+}