fix: add SchemaMapOptions class for options to map schematype

Fix #8318

lib/options/SchemaMapOptions.js

@@ -0,0 +1,43 @@
+'use strict';
+
+const SchemaTypeOptions = require('./SchemaTypeOptions');
+
+/**
+ * The options defined on a Map schematype.
+ *
+ * ####Example:
+ *
+ *     const schema = new Schema({ socialMediaHandles: { type: Map, of: String } });
+ *     schema.path('socialMediaHandles').options; // SchemaMapOptions instance
+ *
+ * @api public
+ * @inherits SchemaTypeOptions
+ * @constructor SchemaMapOptions
+ */
+
+class SchemaMapOptions extends SchemaTypeOptions {}
+
+const opts = require('./propertyOptions');
+
+/**
+ * If set, specifies the type of this map's values. Mongoose will cast
+ * this map's values to the given type.
+ * 
+ * If not set, Mongoose will not cast the map's values.
+ * 
+ * ####Example:
+ *
+ *     // Mongoose will cast `socialMediaHandles` values to strings
+ *     const schema = new Schema({ socialMediaHandles: { type: Map, of: String } });
+ *     schema.path('socialMediaHandles').options.of; // String
+ *
+ * @api public
+ * @property of
+ * @memberOf SchemaMapOptions
+ * @type Function|string
+ * @instance
+ */
+
+Object.defineProperty(SchemaMapOptions.prototype, 'of', opts);
+
+module.exports = SchemaMapOptions;

lib/schema/map.js

@@ -5,6 +5,7 @@
  */
 
 const MongooseMap = require('../types/map');
+const SchemaMapOptions = require('../options/SchemaMapOptions');
 const SchemaType = require('../schematype');
 
 /*!
@@ -42,4 +43,6 @@ class Map extends SchemaType {
   }
 }
 
+Map.prototype.OptionsConstructor = SchemaMapOptions;
+
 module.exports = Map;

test/types.map.test.js

@@ -6,6 +6,7 @@
 
 const start = require('./common');
 
+const SchemaMapOptions = require('../lib/options/SchemaMapOptions');
 const assert = require('assert');
 const co = require('co');
 
@@ -47,6 +48,8 @@ describe('Map', function() {
       }
     });
 
+    assert.ok(TestSchema.path('v').options instanceof SchemaMapOptions);
+
     const Test = db.model('MapTest', TestSchema);
 
     return co(function*() {