feat(document): support defaults option to disable adding defaults …

…to a single document

Fix #8271

lib/document.js

@@ -55,7 +55,8 @@ const specialProperties = utils.specialProperties;
  *
  * @param {Object} obj the values to set
  * @param {Object} [fields] optional object containing the fields which were selected in the query returning this document and any populated paths data
- * @param {Boolean} [skipId] bool, should we auto create an ObjectId _id
+ * @param {Object} [options] various configuration options for the document
+ * @param {Boolean} [options.defaults=true] if `false`, skip applying default values to this document.
  * @inherits NodeJS EventEmitter http://nodejs.org/api/events.html#events_class_events_eventemitter
  * @event `init`: Emitted on a document after it has been retrieved from the db and fully hydrated by Mongoose.
  * @event `save`: Emitted when the document is successfully saved
@@ -67,7 +68,9 @@ function Document(obj, fields, skipId, options) {
     options = skipId;
     skipId = options.skipId;
   }
-  options = options || {};
+  options = Object.assign({}, options);
+  const defaults = get(options, 'defaults', true);
+  options.defaults = defaults;
 
   // Support `browserDocument.js` syntax
   if (this.schema == null) {
@@ -126,9 +129,11 @@ function Document(obj, fields, skipId, options) {
 
     // By default, defaults get applied **before** setting initial values
     // Re: gh-6155
-    $__applyDefaults(this, fields, skipId, exclude, hasIncludedChildren, true, {
-      isNew: this.isNew
-    });
+    if (defaults) {
+      $__applyDefaults(this, fields, skipId, exclude, hasIncludedChildren, true, {
+        isNew: this.isNew
+      });
+    }
   }
 
   if (obj) {
@@ -147,13 +152,13 @@ function Document(obj, fields, skipId, options) {
   // Function defaults get applied **after** setting initial values so they
   // see the full doc rather than an empty one, unless they opt out.
   // Re: gh-3781, gh-6155
-  if (options.willInit) {
+  if (options.willInit && defaults) {
     EventEmitter.prototype.once.call(this, 'init', () => {
       $__applyDefaults(this, fields, skipId, exclude, hasIncludedChildren, false, options.skipDefaults, {
         isNew: this.isNew
       });
     });
-  } else {
+  } else if (defaults) {
     $__applyDefaults(this, fields, skipId, exclude, hasIncludedChildren, false, options.skipDefaults, {
       isNew: this.isNew
     });

lib/types/subdocument.js

@@ -29,7 +29,10 @@ function Subdocument(value, fields, parent, skipId, options) {
   }
   if (parent != null) {
     // If setting a nested path, should copy isNew from parent re: gh-7048
-    options = Object.assign({}, options, { isNew: parent.isNew });
+    options = Object.assign({}, options, {
+      isNew: parent.isNew,
+      defaults: parent.$__.$options.defaults
+    });
   }
   Document.call(this, value, fields, skipId, options);
 

test/document.test.js

@@ -8975,4 +8975,25 @@ describe('document', function() {
     const axl = new Person({ fullName: 'Axl Rose' });
     assert.equal(axl.fullName, 'Axl Rose');
   });
+
+  it('supports skipping defaults on a document (gh-8271)', function() {
+    const testSchema = new mongoose.Schema({
+      testTopLevel: { type: String, default: 'foo' },
+      testNested: {
+        prop: { type: String, default: 'bar' }
+      },
+      testArray: [{ prop: { type: String, defualt: 'baz' } }],
+      testSingleNested: new Schema({
+        prop: { type: String, default: 'qux' }
+      })
+    });
+    const Test = db.model('Test', testSchema);
+
+    const doc = new Test({ testArray: [{}], testSingleNested: {} }, null,
+      { defaults: false });
+    assert.ok(!doc.testTopLevel);
+    assert.ok(!doc.testNested.prop);
+    assert.ok(!doc.testArray[0].prop);
+    assert.ok(!doc.testSingleNested.prop);
+  });
 });