util: code cleanup

Remove some dead code plus some minor refactoring for readability.
The constructor can not be an empty string anymore, so just remove
that check.

PR-URL: https://github.com/nodejs/node/pull/25255
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/internal/util/inspect.js

@@ -211,34 +211,34 @@ Object.defineProperty(inspect, 'defaultOptions', {
 
 // http://en.wikipedia.org/wiki/ANSI_escape_code#graphics
 inspect.colors = Object.assign(Object.create(null), {
-  'bold': [1, 22],
-  'italic': [3, 23],
-  'underline': [4, 24],
-  'inverse': [7, 27],
-  'white': [37, 39],
-  'grey': [90, 39],
-  'black': [30, 39],
-  'blue': [34, 39],
-  'cyan': [36, 39],
-  'green': [32, 39],
-  'magenta': [35, 39],
-  'red': [31, 39],
-  'yellow': [33, 39]
+  bold: [1, 22],
+  italic: [3, 23],
+  underline: [4, 24],
+  inverse: [7, 27],
+  white: [37, 39],
+  grey: [90, 39],
+  black: [30, 39],
+  blue: [34, 39],
+  cyan: [36, 39],
+  green: [32, 39],
+  magenta: [35, 39],
+  red: [31, 39],
+  yellow: [33, 39]
 });
 
 // Don't use 'blue' not visible on cmd.exe
 inspect.styles = Object.assign(Object.create(null), {
-  'special': 'cyan',
-  'number': 'yellow',
-  'bigint': 'yellow',
-  'boolean': 'yellow',
-  'undefined': 'grey',
-  'null': 'bold',
-  'string': 'green',
-  'symbol': 'green',
-  'date': 'magenta',
+  special: 'cyan',
+  number: 'yellow',
+  bigint: 'yellow',
+  boolean: 'yellow',
+  undefined: 'grey',
+  null: 'bold',
+  string: 'green',
+  symbol: 'green',
+  date: 'magenta',
   // "name": intentionally not styling
-  'regexp': 'red'
+  regexp: 'red'
 });
 
 function addQuotes(str, quotes) {
@@ -358,14 +358,10 @@ function getPrefix(constructor, tag, fallback) {
     return `[${fallback}: null prototype] `;
   }
 
-  if (constructor !== '') {
-    if (tag !== '' && constructor !== tag) {
-      return `${constructor} [${tag}] `;
-    }
-    return `${constructor} `;
+  if (tag !== '' && constructor !== tag) {
+    return `${constructor} [${tag}] `;
   }
-
-  return '';
+  return `${constructor} `;
 }
 
 const getBoxedValue = formatPrimitive.bind(null, stylizeNoColor);
@@ -619,16 +615,12 @@ function formatRaw(ctx, value, recurseTimes, typedArray) {
     braces = ['{', '}'];
     if (constructor === 'Object') {
       if (isArgumentsObject(value)) {
-        if (keys.length === 0)
-          return '[Arguments] {}';
         braces[0] = '[Arguments] {';
       } else if (tag !== '') {
         braces[0] = `${getPrefix(constructor, tag, 'Object')}{`;
-        if (keys.length === 0) {
-          return `${braces[0]}}`;
-        }
-      } else if (keys.length === 0) {
-        return '{}';
+      }
+      if (keys.length === 0) {
+        return `${braces[0]}}`;
       }
     } else if (typeof value === 'function') {
       const type = constructor || tag || 'Function';
@@ -822,9 +814,7 @@ function handleMaxCallStackSize(ctx, err, constructor, tag, indentationLvl) {
 
 function formatNumber(fn, value) {
   // Format -0 as '-0'. Checking `value === -0` won't distinguish 0 from -0.
-  if (Object.is(value, -0))
-    return fn('-0', 'number');
-  return fn(`${value}`, 'number');
+  return fn(Object.is(value, -0) ? '-0' : `${value}`, 'number');
 }
 
 function formatBigInt(fn, value) {

test/parallel/test-util-inspect.js

@@ -1853,7 +1853,6 @@ assert.strictEqual(
     util.inspect(new StorageObject()),
     '<[Object: null prototype] {}> {}'
   );
-
 }
 
 // Check that the fallback always works.