assert: Add support for Map and Set in deepEqual

lib/assert.js

@@ -23,6 +23,7 @@
 // UTILITY
 const compare = process.binding('buffer').compare;
 const util = require('util');
+const { isSet, isMap } = process.binding('util');
 const objectToString = require('internal/util').objectToString;
 const Buffer = require('buffer').Buffer;
 
@@ -262,11 +263,12 @@ function _deepEqual(actual, expected, strict, memos) {
     }
   }
 
-  // For all other Object pairs, including Array objects,
+  // For all other Object pairs, including Array objects and Maps,
   // equivalence is determined by having:
   // a) The same number of owned enumerable properties
   // b) The same set of keys/indexes (although not necessarily the same order)
   // c) Equivalent values for every corresponding key/index
+  // d) For Sets and Maps, equal contents
   // Note: this accounts for both named and indexed properties on Arrays.
 
   // Use memos to handle cycles.
@@ -280,9 +282,89 @@ function _deepEqual(actual, expected, strict, memos) {
   memos.actual.push(actual);
   memos.expected.push(expected);
 
+
   return objEquiv(actual, expected, strict, memos);
 }
 
+function setEquiv(a, b, strict, actualVisitedObjects) {
+  // This code currently returns false for this pair of sets:
+  //   assert.deepEqual(new Set(['1', 1]), new Set([1]))
+  //
+  // In theory, all the items in the first set have a corresponding == value in
+  // the second set, but the sets have different sizes. Its a silly case,
+  // and more evidence that deepStrictEqual should always be preferred over
+  // deepEqual. The implementation currently returns false, which is simpler
+  // and slightly faster.
+  if (a.size !== b.size)
+    return false;
+
+  outer: for (const val1 of a) {
+    if (!b.has(val1)) {
+      if (!strict || (typeof val1 === 'object' && val1 !== null)) {
+        // The value doesn't exist in the second set by reference, so we'll go
+        // hunting for something thats deep-equal to it. Note that this is
+        // O(n^2) complexity, and will get slower if large, very similar sets /
+        // maps are nested inside. Unfortunately there's no real way around
+        // this.
+        for (const val2 of b) {
+          if (_deepEqual(val1, val2, strict, actualVisitedObjects))
+            continue outer;
+        }
+      }
+
+      // Not found!
+      return false;
+    }
+  }
+
+  return true;
+}
+
+function mapEquiv(a, b, strict, actualVisitedObjects) {
+  // Caveat: In non-strict mode, this implementation does not handle cases
+  // where maps contain two equivalent-but-not-reference-equal keys.
+  //
+  // For example, maps like this are currently considered not equivalent:
+  if (a.size !== b.size)
+    return false;
+
+  outer: for (const [key1, item1] of a) {
+    // To be able to handle cases like:
+    //   Map([[1, 'a'], ['1', 'b']]) vs Map([['1', 'a'], [1, 'b']])
+    // or:
+    //   Map([[{}, 'a'], [{}, 'b']]) vs Map([[{}, 'b'], [{}, 'a']])
+    // ... we need to consider *all* matching keys, not just the first we find.
+
+    // This check is not strictly necessary if we run the loop below, but it
+    // improves performance of the common case when reference-equal keys exist
+    // (which includes all primitive-valued keys).
+    if (b.has(key1)) {
+      if (_deepEqual(item1, b.get(key1), strict, actualVisitedObjects))
+        continue outer;
+    }
+
+    // Hunt for keys which are deep-equal to key1 in b. Just like setEquiv
+    // above, this hunt makes this function O(n^2) when using objects and lists
+    // as keys
+    if (!strict || (typeof key1 === 'object' && key1 !== null)) {
+      for (const [key2, item2] of b) {
+        // Just for performance. We already checked these keys above.
+        if (key2 === key1)
+          continue;
+
+        if (_deepEqual(key1, key2, strict, actualVisitedObjects) &&
+            _deepEqual(item1, item2, strict, actualVisitedObjects)) {
+          continue outer;
+        }
+      }
+    }
+
+    return false;
+  }
+
+  return true;
+}
+
 function objEquiv(a, b, strict, actualVisitedObjects) {
   // If one of them is a primitive, the other must be the same.
   if (util.isPrimitive(a) || util.isPrimitive(b))
@@ -307,6 +389,22 @@ function objEquiv(a, b, strict, actualVisitedObjects) {
       return false;
   }
 
+  // Sets and maps don't have their entries accessible via normal object
+  // properties.
+  if (isSet(a)) {
+    if (!isSet(b) || !setEquiv(a, b, strict, actualVisitedObjects))
+      return false;
+  } else if (isSet(b)) {
+    return false;
+  }
+
+  if (isMap(a)) {
+    if (!isMap(b) || !mapEquiv(a, b, strict, actualVisitedObjects))
+      return false;
+  } else if (isMap(b)) {
+    return false;
+  }
+
   // The pair must have equivalent values for every corresponding key.
   // Possibly expensive deep test:
   for (i = aKeys.length - 1; i >= 0; i--) {

test/parallel/test-assert-deep.js

@@ -100,11 +100,170 @@ const similar = new Set([
 for (const a of similar) {
   for (const b of similar) {
     if (a !== b) {
-      assert.doesNotThrow(() => assert.deepEqual(a, b));
+      assert.deepEqual(a, b);
       assert.throws(() => assert.deepStrictEqual(a, b),
                     re`${a} deepStrictEqual ${b}`);
     }
   }
 }
 
+function assertDeepAndStrictEqual(a, b) {
+  assert.doesNotThrow(() => assert.deepEqual(a, b));
+  assert.doesNotThrow(() => assert.deepStrictEqual(a, b));
+
+  assert.doesNotThrow(() => assert.deepEqual(b, a));
+  assert.doesNotThrow(() => assert.deepStrictEqual(b, a));
+}
+
+function assertNotDeepOrStrict(a, b) {
+  assert.throws(() => assert.deepEqual(a, b));
+  assert.throws(() => assert.deepStrictEqual(a, b));
+
+  assert.throws(() => assert.deepEqual(b, a));
+  assert.throws(() => assert.deepStrictEqual(b, a));
+}
+
+function assertOnlyDeepEqual(a, b) {
+  assert.doesNotThrow(() => assert.deepEqual(a, b));
+  assert.throws(() => assert.deepStrictEqual(a, b));
+
+  assert.doesNotThrow(() => assert.deepEqual(b, a));
+  assert.throws(() => assert.deepStrictEqual(b, a));
+}
+
+// es6 Maps and Sets
+assertDeepAndStrictEqual(new Set(), new Set());
+assertDeepAndStrictEqual(new Map(), new Map());
+
+assertDeepAndStrictEqual(new Set([1, 2, 3]), new Set([1, 2, 3]));
+assertNotDeepOrStrict(new Set([1, 2, 3]), new Set([1, 2, 3, 4]));
+assertNotDeepOrStrict(new Set([1, 2, 3, 4]), new Set([1, 2, 3]));
+assertDeepAndStrictEqual(new Set(['1', '2', '3']), new Set(['1', '2', '3']));
+assertDeepAndStrictEqual(new Set([[1, 2], [3, 4]]), new Set([[3, 4], [1, 2]]));
+
+assertDeepAndStrictEqual(new Map([[1, 1], [2, 2]]), new Map([[1, 1], [2, 2]]));
+assertDeepAndStrictEqual(new Map([[1, 1], [2, 2]]), new Map([[2, 2], [1, 1]]));
+assertNotDeepOrStrict(new Map([[1, 1], [2, 2]]), new Map([[1, 2], [2, 1]]));
+
+assertNotDeepOrStrict(new Set([1]), [1]);
+assertNotDeepOrStrict(new Set(), []);
+assertNotDeepOrStrict(new Set(), {});
+
+assertNotDeepOrStrict(new Map([['a', 1]]), {a: 1});
+assertNotDeepOrStrict(new Map(), []);
+assertNotDeepOrStrict(new Map(), {});
+
+assertOnlyDeepEqual(new Set(['1']), new Set([1]));
+
+assertOnlyDeepEqual(new Map([['1', 'a']]), new Map([[1, 'a']]));
+assertOnlyDeepEqual(new Map([['a', '1']]), new Map([['a', 1]]));
+
+// This is an awful case, where a map contains multiple equivalent keys:
+assertOnlyDeepEqual(
+  new Map([[1, 'a'], ['1', 'b']]),
+  new Map([['1', 'a'], [1, 'b']])
+);
+assertDeepAndStrictEqual(
+  new Map([[{}, 'a'], [{}, 'b']]),
+  new Map([[{}, 'b'], [{}, 'a']])
+);
+
+{
+  const values = [
+    123,
+    Infinity,
+    0,
+    null,
+    undefined,
+    false,
+    true,
+    {},
+    [],
+    () => {},
+  ];
+  assertDeepAndStrictEqual(new Set(values), new Set(values));
+  assertDeepAndStrictEqual(new Set(values), new Set(values.reverse()));
+
+  const mapValues = values.map((v) => [v, {a: 5}]);
+  assertDeepAndStrictEqual(new Map(mapValues), new Map(mapValues));
+  assertDeepAndStrictEqual(new Map(mapValues), new Map(mapValues.reverse()));
+}
+
+{
+  const s1 = new Set();
+  const s2 = new Set();
+  s1.add(1);
+  s1.add(2);
+  s2.add(2);
+  s2.add(1);
+  assertDeepAndStrictEqual(s1, s2);
+}
+
+{
+  const m1 = new Map();
+  const m2 = new Map();
+  const obj = {a: 5, b: 6};
+  m1.set(1, obj);
+  m1.set(2, 'hi');
+  m1.set(3, [1, 2, 3]);
+
+  m2.set(2, 'hi'); // different order
+  m2.set(1, obj);
+  m2.set(3, [1, 2, 3]); // deep equal, but not reference equal.
+
+  assertDeepAndStrictEqual(m1, m2);
+}
+
+{
+  const m1 = new Map();
+  const m2 = new Map();
+
+  // m1 contains itself.
+  m1.set(1, m1);
+  m2.set(1, new Map());
+
+  assertNotDeepOrStrict(m1, m2);
+}
+
+assert.deepEqual(new Map([[1, 1]]), new Map([[1, '1']]));
+assert.throws(() =>
+  assert.deepStrictEqual(new Map([[1, 1]]), new Map([[1, '1']]))
+);
+
+{
+  // Two equivalent sets / maps with different key/values applied shouldn't be
+  // the same. This is a terrible idea to do in practice, but deepEqual should
+  // still check for it.
+  const s1 = new Set();
+  const s2 = new Set();
+  s1.x = 5;
+  assertNotDeepOrStrict(s1, s2);
+
+  const m1 = new Map();
+  const m2 = new Map();
+  m1.x = 5;
+  assertNotDeepOrStrict(m1, m2);
+}
+
+{
+  // Circular references.
+  const s1 = new Set();
+  s1.add(s1);
+  const s2 = new Set();
+  s2.add(s2);
+  assertDeepAndStrictEqual(s1, s2);
+
+  const m1 = new Map();
+  m1.set(2, m1);
+  const m2 = new Map();
+  m2.set(2, m2);
+  assertDeepAndStrictEqual(m1, m2);
+
+  const m3 = new Map();
+  m3.set(m3, 2);
+  const m4 = new Map();
+  m4.set(m4, 2);
+  assertDeepAndStrictEqual(m3, m4);
+}
+
 /* eslint-enable */