Deep equality check for collection membership

lib/chai/core/assertions.js

@@ -1245,24 +1245,32 @@ module.exports = function (chai, _) {
     );
   });
 
-  function isSubsetOf(subset, superset) {
+  function isSubsetOf(subset, superset, cmp) {
     return subset.every(function(elem) {
-      return superset.indexOf(elem) !== -1;
+      if (!cmp) return superset.indexOf(elem) !== -1;
+
+      return superset.some(function(elem2) {
+        return cmp(elem, elem2);
+      });
     })
   }
 
   /**
    * ### .members(set)
    *
    * Asserts that the target is a superset of `set`,
-   * or that the target and `set` have the same members.
+   * or that the target and `set` have the same strictly-equal (===) members.
+   * Alternately, if the `deep` flag is set, set members are compared for deep
+   * equality.
    *
    *     expect([1, 2, 3]).to.include.members([3, 2]);
    *     expect([1, 2, 3]).to.not.include.members([3, 2, 8]);
    *
    *     expect([4, 2]).to.have.members([2, 4]);
    *     expect([5, 2]).to.not.have.members([5, 2, 1]);
    *
+   *     expect([{ id: 1 }]).to.deep.include.members([{ id: 1 }]);
+   *
    * @name members
    * @param {Array} set
    * @param {String} message _optional_
@@ -1276,9 +1284,11 @@ module.exports = function (chai, _) {
     new Assertion(obj).to.be.an('array');
     new Assertion(subset).to.be.an('array');
 
+    var cmp = flag(this, 'deep') ? _.eql : undefined;
+
     if (flag(this, 'contains')) {
       return this.assert(
-          isSubsetOf(subset, obj)
+          isSubsetOf(subset, obj, cmp)
         , 'expected #{this} to be a superset of #{act}'
         , 'expected #{this} to not be a superset of #{act}'
         , obj
@@ -1287,7 +1297,7 @@ module.exports = function (chai, _) {
     }
 
     this.assert(
-        isSubsetOf(obj, subset) && isSubsetOf(subset, obj)
+        isSubsetOf(obj, subset, cmp) && isSubsetOf(subset, obj, cmp)
         , 'expected #{this} to have the same members as #{act}'
         , 'expected #{this} to not have the same members as #{act}'
         , obj

test/expect.js

@@ -787,6 +787,15 @@ describe('expect', function () {
     expect([5, 4]).not.members([]);
     expect([5, 4]).not.members([6, 3]);
     expect([5, 4]).not.members([5, 4, 2]);
-  })
+    expect([{ id: 1 }]).not.members([{ id: 1 }]);
+  });
+
+  it('deep.members', function() {
+    expect([{ id: 1 }]).deep.members([{ id: 1 }]);
+    expect([{ id: 2 }]).not.deep.members([{ id: 1 }]);
+    err(function(){
+      expect([{ id: 1 }]).deep.members([{ id: 2 }])
+    }, "expected [ { id: 1 } ] to have the same members as [ { id: 2 } ]");
+  });
 
 });