util: add (typed) array length to the default output

lib/internal/util/inspect.js

@@ -117,6 +117,9 @@ const setSizeGetter = uncurryThis(
   ObjectGetOwnPropertyDescriptor(SetPrototype, 'size').get);
 const mapSizeGetter = uncurryThis(
   ObjectGetOwnPropertyDescriptor(MapPrototype, 'size').get);
+const typedArraySizeGetter = uncurryThis(
+  ObjectGetOwnPropertyDescriptor(
+    ObjectGetPrototypeOf(Uint8Array.prototype), 'length').get);
 
 let hexSlice;
 
@@ -567,18 +570,18 @@ function addPrototypeProperties(ctx, main, obj, recurseTimes, isProto, output) {
   } while (++depth !== 3);
 }
 
-function getPrefix(constructor, tag, fallback) {
+function getPrefix(constructor, tag, fallback, size = '') {
   if (constructor === null) {
     if (tag !== '') {
-      return `[${fallback}: null prototype] [${tag}] `;
+      return `[${fallback}${size}: null prototype] [${tag}] `;
     }
-    return `[${fallback}: null prototype] `;
+    return `[${fallback}${size}: null prototype] `;
   }
 
   if (tag !== '' && constructor !== tag) {
-    return `${constructor} [${tag}] `;
+    return `${constructor}${size} [${tag}] `;
   }
-  return `${constructor} `;
+  return `${constructor}${size} `;
 }
 
 // Look up the keys of the object.
@@ -763,58 +766,48 @@ function formatRaw(ctx, value, recurseTimes, typedArray) {
   if (value[SymbolIterator] || constructor === null) {
     noIterator = false;
     if (ArrayIsArray(value)) {
-      keys = getOwnNonIndexProperties(value, filter);
       // Only set the constructor for non ordinary ("Array [...]") arrays.
-      const prefix = getPrefix(constructor, tag, 'Array');
-      braces = [`${prefix === 'Array ' ? '' : prefix}[`, ']'];
+      const prefix = (constructor !== 'Array' || tag !== '') ?
+        getPrefix(constructor, tag, 'Array', `(${value.length})`) :
+        '';
+      keys = getOwnNonIndexProperties(value, filter);
+      braces = [`${prefix}[`, ']'];
       if (value.length === 0 && keys.length === 0 && protoProps === undefined)
         return `${braces[0]}]`;
       extrasType = kArrayExtrasType;
       formatter = formatArray;
     } else if (isSet(value)) {
       const size = setSizeGetter(value);
+      const prefix = getPrefix(constructor, tag, 'Set', `(${size})`);
       keys = getKeys(value, ctx.showHidden);
-      let prefix = '';
-      if (constructor !== null) {
-        if (constructor === tag)
-          tag = '';
-        prefix = getPrefix(`${constructor}(${size})`, tag, '');
-        formatter = formatSet.bind(null, value, size);
-      } else {
-        prefix = getPrefix(constructor, tag, `Set(${size})`);
-        formatter = formatSet.bind(null, SetPrototypeValues(value), size);
-      }
+      formatter = constructor !== null ?
+        formatSet.bind(null, value) :
+        formatSet.bind(null, SetPrototypeValues(value));
       if (size === 0 && keys.length === 0 && protoProps === undefined)
         return `${prefix}{}`;
       braces = [`${prefix}{`, '}'];
     } else if (isMap(value)) {
       const size = mapSizeGetter(value);
+      const prefix = getPrefix(constructor, tag, 'Map', `(${size})`);
       keys = getKeys(value, ctx.showHidden);
-      let prefix = '';
-      if (constructor !== null) {
-        if (constructor === tag)
-          tag = '';
-        prefix = getPrefix(`${constructor}(${size})`, tag, '');
-        formatter = formatMap.bind(null, value, size);
-      } else {
-        prefix = getPrefix(constructor, tag, `Map(${size})`);
-        formatter = formatMap.bind(null, MapPrototypeEntries(value), size);
-      }
+      formatter = constructor !== null ?
+        formatMap.bind(null, value) :
+        formatMap.bind(null, MapPrototypeEntries(value));
       if (size === 0 && keys.length === 0 && protoProps === undefined)
         return `${prefix}{}`;
       braces = [`${prefix}{`, '}'];
     } else if (isTypedArray(value)) {
       keys = getOwnNonIndexProperties(value, filter);
       let bound = value;
-      let prefix = '';
+      let fallback = '';
       if (constructor === null) {
         const constr = findTypedConstructor(value);
-        prefix = getPrefix(constructor, tag, constr.name);
+        fallback = constr.name;
         // Reconstruct the array information.
         bound = new constr(value);
-      } else {
-        prefix = getPrefix(constructor, tag);
       }
+      const size = typedArraySizeGetter(value);
+      const prefix = getPrefix(constructor, tag, fallback, `(${size})`);
       braces = [`${prefix}[`, ']'];
       if (value.length === 0 && keys.length === 0 && !ctx.showHidden)
         return `${braces[0]}]`;
@@ -1430,7 +1423,7 @@ function formatTypedArray(value, ctx, ignored, recurseTimes) {
   return output;
 }
 
-function formatSet(value, size, ctx, ignored, recurseTimes) {
+function formatSet(value, ctx, ignored, recurseTimes) {
   const output = [];
   ctx.indentationLvl += 2;
   for (const v of value) {
@@ -1440,7 +1433,7 @@ function formatSet(value, size, ctx, ignored, recurseTimes) {
   return output;
 }
 
-function formatMap(value, size, ctx, ignored, recurseTimes) {
+function formatMap(value, ctx, ignored, recurseTimes) {
   const output = [];
   ctx.indentationLvl += 2;
   for (const [k, v] of value) {

test/parallel/test-assert-deep.js

@@ -51,8 +51,8 @@ assert.throws(
   {
     code: 'ERR_ASSERTION',
     message: `${defaultMsgStartFull} ... Lines skipped\n\n` +
-             '+ Uint8Array [\n' +
-             '- Buffer [Uint8Array] [\n    120,\n...\n    122,\n    10\n  ]'
+             '+ Uint8Array(4) [\n' +
+             '- Buffer(4) [Uint8Array] [\n    120,\n...\n    122,\n    10\n  ]'
   }
 );
 assert.deepEqual(arr, buf);
@@ -66,7 +66,7 @@ assert.deepEqual(arr, buf);
     {
       code: 'ERR_ASSERTION',
       message: `${defaultMsgStartFull}\n\n` +
-               '  Buffer [Uint8Array] [\n' +
+               '  Buffer(4) [Uint8Array] [\n' +
                '    120,\n' +
                '    121,\n' +
                '    122,\n' +
@@ -86,7 +86,7 @@ assert.deepEqual(arr, buf);
     {
       code: 'ERR_ASSERTION',
       message: `${defaultMsgStartFull}\n\n` +
-               '  Uint8Array [\n' +
+               '  Uint8Array(4) [\n' +
                '    120,\n' +
                '    121,\n' +
                '    122,\n' +

test/parallel/test-buffer-inspect.js

@@ -58,7 +58,7 @@ b.inspect = undefined;
 b.prop = new Uint8Array(0);
 assert.strictEqual(
   util.inspect(b),
-  '<Buffer 31 32, inspect: undefined, prop: Uint8Array []>'
+  '<Buffer 31 32, inspect: undefined, prop: Uint8Array(0) []>'
 );
 
 b = Buffer.alloc(0);

test/parallel/test-fs-read-empty-buffer.js

@@ -15,7 +15,7 @@ assert.throws(
   {
     code: 'ERR_INVALID_ARG_VALUE',
     message: 'The argument \'buffer\' is empty and cannot be written. ' +
-    'Received Uint8Array []'
+    'Received Uint8Array(0) []'
   }
 );
 
@@ -24,7 +24,7 @@ assert.throws(
   {
     code: 'ERR_INVALID_ARG_VALUE',
     message: 'The argument \'buffer\' is empty and cannot be written. ' +
-    'Received Uint8Array []'
+    'Received Uint8Array(0) []'
   }
 );
 
@@ -35,7 +35,7 @@ assert.throws(
     {
       code: 'ERR_INVALID_ARG_VALUE',
       message: 'The argument \'buffer\' is empty and cannot be written. ' +
-               'Received Uint8Array []'
+               'Received Uint8Array(0) []'
     }
   );
 })();

test/parallel/test-util-format.js

@@ -158,7 +158,7 @@ assert.strictEqual(util.format('%s', () => 5), '() => 5');
   class Foobar extends Array { aaa = true; }
   assert.strictEqual(
     util.format('%s', new Foobar(5)),
-    'Foobar [ <5 empty items>, aaa: true ]'
+    'Foobar(5) [ <5 empty items>, aaa: true ]'
   );
 
   // Subclassing: