util: use [Array] for deeply nested arrays

Prefer `[Array]` over `[Object]` because the latter is confusing.

PR-URL: #12046
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>

Author: addaleax

lib/util.js

@@ -586,6 +586,8 @@ function formatValue(ctx, value, recurseTimes) {
   if (recurseTimes < 0) {
     if (isRegExp(value)) {
       return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
+    } else if (Array.isArray(value)) {
+      return ctx.stylize('[Array]', 'special');
     } else {
       return ctx.stylize('[Object]', 'special');
     }

test/parallel/test-util-inspect-proxy.js

@@ -48,13 +48,13 @@ const expected1 = 'Proxy [ {}, {} ]';
 const expected2 = 'Proxy [ Proxy [ {}, {} ], {} ]';
 const expected3 = 'Proxy [ Proxy [ Proxy [ {}, {} ], {} ], Proxy [ {}, {} ] ]';
 const expected4 = 'Proxy [ Proxy [ {}, {} ], Proxy [ Proxy [ {}, {} ], {} ] ]';
-const expected5 = 'Proxy [ Proxy [ Proxy [ Proxy [Object], {} ],' +
+const expected5 = 'Proxy [ Proxy [ Proxy [ Proxy [Array], {} ],' +
                   ' Proxy [ {}, {} ] ],\n  Proxy [ Proxy [ {}, {} ]' +
-                  ', Proxy [ Proxy [Object], {} ] ] ]';
-const expected6 = 'Proxy [ Proxy [ Proxy [ Proxy [Object], Proxy [Object]' +
-                  ' ],\n    Proxy [ Proxy [Object], Proxy [Object] ] ],\n' +
-                  '  Proxy [ Proxy [ Proxy [Object], Proxy [Object] ],\n' +
-                  '    Proxy [ Proxy [Object], Proxy [Object] ] ] ]';
+                  ', Proxy [ Proxy [Array], {} ] ] ]';
+const expected6 = 'Proxy [ Proxy [ Proxy [ Proxy [Array], Proxy [Array]' +
+                  ' ],\n    Proxy [ Proxy [Array], Proxy [Array] ] ],\n' +
+                  '  Proxy [ Proxy [ Proxy [Array], Proxy [Array] ],\n' +
+                  '    Proxy [ Proxy [Array], Proxy [Array] ] ] ]';
 assert.strictEqual(util.inspect(proxy1, opts), expected1);
 assert.strictEqual(util.inspect(proxy2, opts), expected2);
 assert.strictEqual(util.inspect(proxy3, opts), expected3);

test/parallel/test-util-inspect.js

@@ -72,6 +72,8 @@ assert.strictEqual(util.inspect({'a': {'b': { 'c': 2}}}, false, 0),
                    '{ a: [Object] }');
 assert.strictEqual(util.inspect({'a': {'b': { 'c': 2}}}, false, 1),
                    '{ a: { b: [Object] } }');
+assert.strictEqual(util.inspect({'a': {'b': ['c']}}, false, 1),
+                   '{ a: { b: [Array] } }');
 assert.strictEqual(util.inspect(Object.create({},
   {visible: {value: 1, enumerable: true}, hidden: {value: 2}})),
                    '{ visible: 1 }'