util: use average bias while grouping arrays

This makes sure that strongly deviating entry length are taken into account while grouping arrays. PR-URL: #28070 Refs: #27690 Reviewed-By: James M Snell <jasnell@gmail.com>
nodejs · Jun 18, 2019 · b6f113b · b6f113b
1 parent 7e61760
commit b6f113b
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diff --git a/lib/internal/util/inspect.js b/lib/internal/util/inspect.js
@@ -972,7 +972,8 @@ function groupArrayElements(ctx, output, value) {
       (totalLength / actualMax > 5 || maxLength <= 6)) {
 
     const approxCharHeights = 2.5;
-    const biasedMax = Math.max(actualMax - 4, 1);
+    const averageBias = Math.sqrt(actualMax - totalLength / output.length);
+    const biasedMax = Math.max(actualMax - 3 - averageBias, 1);
     // Dynamically check how many columns seem possible.
     const columns = Math.min(
       // Ideally a square should be drawn. We expect a character to be about 2.5

diff --git a/test/parallel/test-util-inspect.js b/test/parallel/test-util-inspect.js
@@ -2252,14 +2252,12 @@ assert.strictEqual(
 
   expected = [
     '[',
-    '  1, 1,         1,',
-    '  1, 1,         1,',
-    '  1, 1,         1,',
-    '  1, 1,         1,',
-    '  1, 1,         1,',
-    '  1, 1,         1,',
-    '  1, 1,         1,',
-    '  1, 1,         1,',
+    '  1, 1,         1, 1,',
+    '  1, 1,         1, 1,',
+    '  1, 1,         1, 1,',
+    '  1, 1,         1, 1,',
+    '  1, 1,         1, 1,',
+    '  1, 1,         1, 1,',
     '  1, 1, 123456789',
     ']'
   ].join('\n');