util: improve inspect edge cases

This makes sure `compact` number mode causes small proxies and map
entries to be printed on a single line.

It also fixed the line break calculation for `compact` mode when not
set to `true`. It now also adds the additional whitespace, comma and
quotes to the formula to prevent exceeding the `breakLength`.

PR-URL: #27109
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Minwoo Jung <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>

Author: BridgeAR

lib/internal/util/inspect.js

@@ -424,7 +424,8 @@ function formatProxy(ctx, proxy, recurseTimes) {
     formatValue(ctx, proxy[1], recurseTimes)
   ];
   ctx.indentationLvl -= 2;
-  return reduceToSingleString(ctx, res, '', ['Proxy [', ']']);
+  return reduceToSingleString(
+    ctx, res, '', ['Proxy [', ']'], kArrayExtrasType, recurseTimes);
 }
 
 function findTypedConstructor(value) {
@@ -786,37 +787,8 @@ function formatRaw(ctx, value, recurseTimes, typedArray) {
     }
   }
 
-  let combine = false;
-  if (typeof ctx.compact === 'number') {
-    // Memorize the original output length. In case the the output is grouped,
-    // prevent lining up the entries on a single line.
-    const entries = output.length;
-    // Group array elements together if the array contains at least six separate
-    // entries.
-    if (extrasType === kArrayExtrasType && output.length > 6) {
-      output = groupArrayElements(ctx, output);
-    }
-    // `ctx.currentDepth` is set to the most inner depth of the currently
-    // inspected object part while `recurseTimes` is the actual current depth
-    // that is inspected.
-    //
-    // Example:
-    //
-    // const a = { first: [ 1, 2, 3 ], second: { inner: [ 1, 2, 3 ] } }
-    //
-    // The deepest depth of `a` is 2 (a.second.inner) and `a.first` has a max
-    // depth of 1.
-    //
-    // Consolidate all entries of the local most inner depth up to
-    // `ctx.compact`, as long as the properties are smaller than
-    // `ctx.breakLength`.
-    if (ctx.currentDepth - recurseTimes < ctx.compact &&
-        entries === output.length) {
-      combine = true;
-    }
-  }
-
-  const res = reduceToSingleString(ctx, output, base, braces, combine);
+  const res = reduceToSingleString(
+    ctx, output, base, braces, extrasType, recurseTimes);
   const budget = ctx.budget[ctx.indentationLvl] || 0;
   const newLength = budget + res.length;
   ctx.budget[ctx.indentationLvl] = newLength;
@@ -984,9 +956,10 @@ function formatBigInt(fn, value) {
 function formatPrimitive(fn, value, ctx) {
   if (typeof value === 'string') {
     if (ctx.compact !== true &&
-      ctx.indentationLvl + value.length > ctx.breakLength &&
-      value.length > kMinLineLength) {
-      const rawMaxLineLength = ctx.breakLength - ctx.indentationLvl;
+        ctx.indentationLvl + value.length + 4 > ctx.breakLength &&
+        value.length > kMinLineLength) {
+      // Subtract the potential quotes, the space and the plus as well (4).
+      const rawMaxLineLength = ctx.breakLength - ctx.indentationLvl - 4;
       const maxLineLength = Math.max(rawMaxLineLength, kMinLineLength);
       const lines = Math.ceil(value.length / maxLineLength);
       const averageLineLength = Math.ceil(value.length / lines);
@@ -1231,7 +1204,8 @@ function formatMapIterInner(ctx, recurseTimes, entries, state) {
         formatValue(ctx, entries[pos], recurseTimes),
         formatValue(ctx, entries[pos + 1], recurseTimes)
       ];
-      output[i] = reduceToSingleString(ctx, res, '', ['[', ']']);
+      output[i] = reduceToSingleString(
+        ctx, res, '', ['[', ']'], kArrayExtrasType, recurseTimes);
     }
   }
   ctx.indentationLvl -= 2;
@@ -1368,17 +1342,43 @@ function isBelowBreakLength(ctx, output, start, base) {
   return base === '' || !base.includes('\n');
 }
 
-function reduceToSingleString(ctx, output, base, braces, combine = false) {
+function reduceToSingleString(
+  ctx, output, base, braces, extrasType, recurseTimes) {
   if (ctx.compact !== true) {
-    if (combine) {
-      // Line up all entries on a single line in case the entries do not exceed
-      // `breakLength`. Add 10 as constant to start next to all other factors
-      // that may reduce `breakLength`.
-      const start = output.length + ctx.indentationLvl +
-                    braces[0].length + base.length + 10;
-      if (isBelowBreakLength(ctx, output, start, base)) {
-        return `${base ? `${base} ` : ''}${braces[0]} ${join(output, ', ')} ` +
-          braces[1];
+    if (typeof ctx.compact === 'number' && ctx.compact >= 1) {
+      // Memorize the original output length. In case the the output is grouped,
+      // prevent lining up the entries on a single line.
+      const entries = output.length;
+      // Group array elements together if the array contains at least six
+      // separate entries.
+      if (extrasType === kArrayExtrasType && entries > 6) {
+        output = groupArrayElements(ctx, output);
+      }
+      // `ctx.currentDepth` is set to the most inner depth of the currently
+      // inspected object part while `recurseTimes` is the actual current depth
+      // that is inspected.
+      //
+      // Example:
+      //
+      // const a = { first: [ 1, 2, 3 ], second: { inner: [ 1, 2, 3 ] } }
+      //
+      // The deepest depth of `a` is 2 (a.second.inner) and `a.first` has a max
+      // depth of 1.
+      //
+      // Consolidate all entries of the local most inner depth up to
+      // `ctx.compact`, as long as the properties are smaller than
+      // `ctx.breakLength`.
+      if (ctx.currentDepth - recurseTimes < ctx.compact &&
+          entries === output.length) {
+        // Line up all entries on a single line in case the entries do not
+        // exceed `breakLength`. Add 10 as constant to start next to all other
+        // factors that may reduce `breakLength`.
+        const start = output.length + ctx.indentationLvl +
+                      braces[0].length + base.length + 10;
+        if (isBelowBreakLength(ctx, output, start, base)) {
+          return `${base ? `${base} ` : ''}${braces[0]} ${join(output, ', ')}` +
+            ` ${braces[1]}`;
+        }
       }
     }
     // Line up each entry on an individual line.

test/parallel/test-util-inspect.js

@@ -1674,7 +1674,7 @@ assert.strictEqual(util.inspect('"\'${a}'), "'\"\\'${a}'");
       return 'BazError';
     }
   }, undefined]
-].forEach(([Class, message, messages], i) => {
+].forEach(([Class, message], i) => {
   console.log('Test %i', i);
   const foo = new Class(message);
   const name = foo.name;