util: improve inspect's customInspect performance

This improves the performance to copy user options that are then passed through to the custom inspect function. The performance improvement depends on the complexity of the custom inspect function. For very basic cases this is 100% faster than before. PR-URL: #30659 Reviewed-By: James M Snell <[email protected]> Reviewed-By: Michaël Zasso <[email protected]> Reviewed-By: Anto Aravinth <[email protected]>
nodejs · Jan 14, 2020 · 1fbd7ac · 1fbd7ac
1 parent d4b41f6
commit 1fbd7ac
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Showing 2 changed files with 23 additions and 9 deletions.
diff --git a/lib/internal/util/inspect.js b/lib/internal/util/inspect.js
@@ -121,6 +121,8 @@ const builtInObjects = new Set(
   ObjectGetOwnPropertyNames(global).filter((e) => /^([A-Z][a-z]+)+$/.test(e))
 );
 
+// These options must stay in sync with `getUserOptions`. So if any option will
+// be added or removed, `getUserOptions` must also be updated accordingly.
 const inspectDefaultOptions = ObjectSeal({
   showHidden: false,
   depth: 2,
@@ -176,13 +178,20 @@ const meta = [
 ];
 
 function getUserOptions(ctx) {
-  const obj = { stylize: ctx.stylize };
-  for (const key of ObjectKeys(inspectDefaultOptions)) {
-    obj[key] = ctx[key];
-  }
-  if (ctx.userOptions === undefined)
-    return obj;
-  return { ...obj, ...ctx.userOptions };
+  return {
+    stylize: ctx.stylize,
+    showHidden: ctx.showHidden,
+    depth: ctx.depth,
+    colors: ctx.colors,
+    customInspect: ctx.customInspect,
+    showProxy: ctx.showProxy,
+    maxArrayLength: ctx.maxArrayLength,
+    breakLength: ctx.breakLength,
+    compact: ctx.compact,
+    sorted: ctx.sorted,
+    getters: ctx.getters,
+    ...ctx.userOptions
+  };
 }
 
 /**

diff --git a/test/parallel/test-util-inspect.js b/test/parallel/test-util-inspect.js
@@ -883,6 +883,10 @@ util.inspect({ hasOwnProperty: null });
     assert.strictEqual(opts.budget, undefined);
     assert.strictEqual(opts.indentationLvl, undefined);
     assert.strictEqual(opts.showHidden, false);
+    assert.deepStrictEqual(
+      new Set(Object.keys(util.inspect.defaultOptions).concat(['stylize'])),
+      new Set(Object.keys(opts))
+    );
     opts.showHidden = true;
     return { [util.inspect.custom]: common.mustCall((depth, opts2) => {
       assert.deepStrictEqual(clone, opts2);
@@ -909,10 +913,11 @@ util.inspect({ hasOwnProperty: null });
 }
 
 {
-  const subject = { [util.inspect.custom]: common.mustCall((depth) => {
+  const subject = { [util.inspect.custom]: common.mustCall((depth, opts) => {
     assert.strictEqual(depth, null);
+    assert.strictEqual(opts.compact, true);
   }) };
-  util.inspect(subject, { depth: null });
+  util.inspect(subject, { depth: null, compact: true });
 }
 
 {