assert,util: improve performance

This improves the performance for array comparison by making the sparse array detection simpler. On top of that it adds a fast path for sets and maps that only contain objects as key.
BridgeAR · Mar 7, 2025 · Mar 8, 2025 · Mar 8, 2025 · Mar 8, 2025 · Mar 8, 2025
commit 5c40578930d478555d9bcd26667d2a2361183fdf
diff --git a/lib/internal/util/comparisons.js b/lib/internal/util/comparisons.js
@@ -559,6 +559,35 @@ function partialObjectSetEquiv(a, b, mode, set, memo) {
   }
 }
 
+function setObjectEquiv(a, b, mode, set, memo) {
+  if (mode === kPartial) {
+    return partialObjectSetEquiv(a, b, mode, set, memo);
+  }
+  // Fast path for objects only
+  if (mode === kStrict && set.size === a.size) {
+    for (const val of a) {
+      if (!setHasEqualElement(set, val, mode, memo)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  for (const val of a) {
+    // Primitive values have already been handled above.
+    if (typeof val === 'object') {
+      if (!b.has(val) && !setHasEqualElement(set, val, mode, memo)) {
+        return false;
+      }
+    } else if (mode === kLoose &&
+              !b.has(val) &&
+              !setHasEqualElement(set, val, mode, memo)) {
+      return false;
+    }
+  }
+  return set.size === 0;
+}
+
 function setEquiv(a, b, mode, memo) {
   // This is a lazily initiated Set of entries which have to be compared
   // pairwise.
@@ -584,22 +613,7 @@ function setEquiv(a, b, mode, memo) {
   }
 
   if (set !== null) {
-    if (mode === kPartial) {
-      return partialObjectSetEquiv(a, b, mode, set, memo);
-    }
-    for (const val of a) {
-      // Primitive values have already been handled above.
-      if (typeof val === 'object' && val !== null) {
-        if (!b.has(val) && !setHasEqualElement(set, val, mode, memo)) {
-          return false;
-        }
-      } else if (mode === kLoose &&
-                !b.has(val) &&
-                !setHasEqualElement(set, val, mode, memo)) {
-        return false;
-      }
-    }
-    return set.size === 0;
+    return setObjectEquiv(a, b, mode, set, memo);
   }
 
   return true;
@@ -640,6 +654,35 @@ function partialObjectMapEquiv(a, b, mode, set, memo) {
   }
 }
 
+function mapObjectEquivalence(a, b, mode, set, memo) {
+  if (mode === kPartial) {
+    return partialObjectMapEquiv(a, b, mode, set, memo);
+  }
+  // Fast path for objects only
+  if (mode === kStrict && set.size === a.size) {
+    for (const { 0: key1, 1: item1 } of a) {
+      if (!mapHasEqualEntry(set, b, key1, item1, mode, memo)) {
+        return false;
+      }
+    }
+    return true;
+  }
+  for (const { 0: key1, 1: item1 } of a) {
+    if (typeof key1 === 'object' && key1 !== null) {
+      if (!mapHasEqualEntry(set, b, key1, item1, mode, memo))
+        return false;
+    } else if (set.size === 0) {
+      return true;
+    } else if (mode === kLoose &&
+              (!b.has(key1) ||
+                !innerDeepEqual(item1, b.get(key1), mode, memo)) &&
+              !mapHasEqualEntry(set, b, key1, item1, mode, memo)) {
+      return false;
+    }
+  }
+  return set.size === 0;
+}
+
 function mapEquiv(a, b, mode, memo) {
   let set = null;
 
@@ -675,21 +718,7 @@ function mapEquiv(a, b, mode, memo) {
   }
 
   if (set !== null) {
-    if (mode === kPartial) {
-      return partialObjectMapEquiv(a, b, mode, set, memo);
-    }
-    for (const { 0: key1, 1: item1 } of a) {
-      if (typeof key1 === 'object' && key1 !== null) {
-        if (!mapHasEqualEntry(set, b, key1, item1, mode, memo))
-          return false;
-      } else if (mode === kLoose &&
-                (!b.has(key1) ||
-                  !innerDeepEqual(item1, b.get(key1), mode, memo)) &&
-                !mapHasEqualEntry(set, b, key1, item1, mode, memo)) {
-        return false;
-      }
-    }
-    return set.size === 0;
+    return mapObjectEquivalence(a, b, mode, set, memo);
   }
 
   return true;
@@ -737,6 +766,24 @@ function partialArrayEquiv(a, b, mode, memos) {
   return true;
 }
 
+function sparseArrayEquiv(a, b, mode, memos, i) {
+  // TODO(BridgeAR): Use internal method to only get index properties. The
+  // same applies to the partial implementation.
+  const keysA = ObjectKeys(a);
+  const keysB = ObjectKeys(b);
+  if (keysA.length !== keysB.length) {
+    return false;
+  }
+  for (; i < keysA.length; i++) {
+    const key = keysA[i];
+    if (!ObjectPrototypeHasOwnProperty(b, key) ||
+        !innerDeepEqual(a[key], b[key], mode, memos)) {
+      return false;
+    }
+  }
+  return true;
+}
+
 function objEquiv(a, b, mode, keys2, memos, iterationType) {
   // The pair must have equivalent values for every corresponding key.
   if (keys2.length > 0) {
@@ -755,23 +802,13 @@ function objEquiv(a, b, mode, keys2, memos, iterationType) {
       if (!innerDeepEqual(a[i], b[i], mode, memos)) {
         return false;
       }
-      const isOwnProperty = ObjectPrototypeHasOwnProperty(a, i);
-      if (isOwnProperty !== ObjectPrototypeHasOwnProperty(b, i)) {
+      const isSparseA = a[i] === undefined && !ObjectPrototypeHasOwnProperty(a, i);
+      const isSparseB = b[i] === undefined && !ObjectPrototypeHasOwnProperty(b, i);
+      if (isSparseA !== isSparseB) {
         return false;
       }
-      if (!isOwnProperty) {
-        // Array is sparse.
-        // TODO(BridgeAR): Use internal method to only get index properties. The
-        // same applies to the partial implementation.
-        const keysA = ObjectKeys(a);
-        for (; i < keysA.length; i++) {
-          const key = keysA[i];
-          if (!ObjectPrototypeHasOwnProperty(b, key) ||
-              !innerDeepEqual(a[key], b[key], mode, memos)) {
-            return false;
-          }
-        }
-        return keysA.length === ObjectKeys(b).length;
+      if (isSparseA) {
+        return sparseArrayEquiv(a, b, mode, memos, i);
       }
     }
   } else if (iterationType === kIsSet) {