assert: add support for Set and Map

Previously, assert.deepEqual used on maps and sets was not functioning
correctly.

This change adds support for correctly comparing Maps and Sets.

For Maps, comparison is done by iterating over each item in the first
Map and verifying that the key exists and the value is the same (depending
on whether strict is applied).

For Sets, each item is iterated over in the first Set and checked if it
exists in the other Set.

For both Maps and Sets, the size of both being compared is checked as
well.

Author: evanlucas

lib/assert.js

@@ -185,6 +185,36 @@ function isArguments(object) {
   return Object.prototype.toString.call(object) == '[object Arguments]';
 }
 
+function compareMaps(a, b, strict) {
+  // check size of the maps
+  if (a.size !== b.size)
+    return false;
+
+  // iterate over all keys and check if they exist in the other
+  for (let kvs of a) {
+    const key = kvs[0];
+    const val = kvs[1];
+    if (!b.has(key)) {
+      return false;
+    }
+
+    if (!_deepEqual(val, b.get(key), strict))
+      return false;
+  }
+  return true;
+}
+
+function compareSets(a, b) {
+  if (a.size !== b.size)
+    return false;
+
+  for (let item of a) {
+    if (!b.has(item))
+      return false;
+  }
+  return true;
+}
+
 function objEquiv(a, b, strict) {
   if (a === null || a === undefined || b === null || b === undefined)
     return false;
@@ -202,6 +232,13 @@ function objEquiv(a, b, strict) {
     b = pSlice.call(b);
     return _deepEqual(a, b, strict);
   }
+  const aStr = Object.prototype.toString.call(a);
+  const bStr = Object.prototype.toString.call(b);
+  if (aStr === '[object Map]' && bStr === '[object Map]') {
+    return compareMaps(a, b, strict);
+  } else if (aStr === '[object Set]' && bStr === '[object Set]') {
+    return compareSets(a, b);
+  }
   var ka = Object.keys(a),
       kb = Object.keys(b),
       key, i;

test/parallel/test-assert.js

@@ -465,4 +465,63 @@ testBlockTypeError(assert.doesNotThrow, null);
 testBlockTypeError(assert.throws, undefined);
 testBlockTypeError(assert.doesNotThrow, undefined);
 
+// Map deep equal, deep strict equal
+const map1 = new Map();
+const map2 = new Map();
+map1.set('1', '2');
+map2.set('1', '2');
+assert.deepEqual(map1, map2);
+map1.set('2', '2');
+assert.throws(function() {
+  assert.deepEqual(map1, map2);
+});
+map1.delete('2');
+map2.set('1', 2);
+assert.deepEqual(map1, map2);
+assert.throws(function() {
+  assert.deepStrictEqual(map1, map2);
+});
+map1.clear();
+map2.clear();
+map1.set(NaN, 'not a number');
+map2.set(NaN, 'not a number');
+assert.deepEqual(map1, map2);
+map1.clear();
+map2.clear();
+map1.set('1', { name: 'test' });
+map2.set('1', { name: 'test' });
+assert.deepStrictEqual(map1, map2);
+map1.clear();
+map2.clear();
+// verify that insertion order doesn't matter
+map1.set('1', '1');
+map1.set('2', '2');
+map2.set('2', '2');
+map2.set('1', '1');
+assert.deepEqual(map1, map2);
+
+// Set deep equal, deep strict equal
+var set1 = new Set();
+var set2 = new Set();
+set1.add(1);
+set2.add(1);
+assert.deepEqual(set1, set2);
+set1.add(2);
+assert.throws(function() {
+  assert.deepEqual(set1, set2);
+});
+set1.delete(2);
+set2.delete(1);
+set2.add('1');
+// throws because we can't really check without being strict
+assert.throws(function() {
+  assert.deepEqual(set1, set2);
+});
+
+assert.deepEqual(new Set([NaN]), new Set([NaN]));
+// verify that insertion order doesn't matter
+set1 = new Set([1, 2]);
+set2 = new Set([2, 1]);
+assert.deepEqual(set1, set2);
+
 console.log('All OK');