Repository: nodejs/node
Pull request: assert: optimize partial comparison of two `Set`s

We can skip the conversion to an array of the expected items as we're only iterating over them. Using a labelled `continue` should also slightly improve perf as we no longer need to keep a `found` boolean value and check its value.
I'm also removing the `TODO` that no longer applies (I suggested adding it when there were plans for a `assert.includes` method in the PR which have since been abandoned). Lastly I'm using the `SafeSet` methods to iterate over the `Set` instances to be consistent with how we iterate over `Map` instances just a few lines above.
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Changed files:
filename: lib/assert.js
patch: @@ -414,33 +414,25 @@ function compareBranch(
   }
 
   // Check for Set object equality
-  // TODO(aduh95): switch to `SetPrototypeIsSubsetOf` when it's available
   if (isSet(actual) && isSet(expected)) {
     if (expected.size > actual.size) {
       return false; // `expected` can't be a subset if it has more elements
     }
 
     if (isDeepEqual === undefined) lazyLoadComparison();
 
-    const actualArray = ArrayFrom(actual);
-    const expectedArray = ArrayFrom(expected);
+    const actualArray = ArrayFrom(FunctionPrototypeCall(SafeSet.prototype[SymbolIterator], actual));
+    const expectedIterator = FunctionPrototypeCall(SafeSet.prototype[SymbolIterator], expected);
     const usedIndices = new SafeSet();
 
-    for (let expectedIdx = 0; expectedIdx < expectedArray.length; expectedIdx++) {
-      const expectedItem = expectedArray[expectedIdx];
-      let found = false;
-
+    expectedIteration: for (const expectedItem of expectedIterator) {
       for (let actualIdx = 0; actualIdx < actualArray.length; actualIdx++) {
         if (!usedIndices.has(actualIdx) && isDeepStrictEqual(actualArray[actualIdx], expectedItem)) {
           usedIndices.add(actualIdx);
-          found = true;
-          break;
+          continue expectedIteration;
         }
       }
-
-      if (!found) {
-        return false;
-      }
+      return false;
     }
 
     return true;