feat: Add comment to MongoDB query via Parse.Query.comment (#2088)

integration/test/ParseQueryTest.js

@@ -2401,4 +2401,19 @@ describe('Parse Query', () => {
     expect(results[1].get('arrayField')).toEqual([{ subfield: 1 }]);
     expect(results[2].get('arrayField')).toEqual(null);
   });
+
+  it('can query and send a comment', async () => {
+    const obj1 = new TestObject({ number: 1 });
+    const obj2 = new TestObject({ number: 2 });
+    const obj3 = new TestObject({ number: 3 });
+    await Parse.Object.saveAll([obj1, obj2, obj3]);
+
+    const query = new Parse.Query(TestObject);
+    const comment = 'Hello Parse';
+    query.comment(comment);
+    query.explain();
+    const explain = await query.find();
+    assert.equal(explain.command.comment, comment);
+  });
+
 });

src/ParseQuery.js

@@ -36,6 +36,7 @@ export type QueryJSON = {
   readPreference?: string,
   includeReadPreference?: string,
   subqueryReadPreference?: string,
+  comment?: string,
 };
 
 /**
@@ -242,6 +243,7 @@ class ParseQuery {
   _hint: mixed;
   _explain: boolean;
   _xhrRequest: any;
+  _comment: string;
 
   /**
    * @param {(string | Parse.Object)} objectClass An instance of a subclass of Parse.Object, or a Parse className string.
@@ -283,6 +285,7 @@ class ParseQuery {
       task: null,
       onchange: () => {},
     };
+    this._comment = null;
   }
 
   /**
@@ -468,6 +471,9 @@ class ParseQuery {
     if (this._explain) {
       params.explain = true;
     }
+    if(this._comment) {
+      params.comment = this._comment;
+    }
     for (const key in this._extraOptions) {
       params[key] = this._extraOptions[key];
     }
@@ -553,6 +559,10 @@ class ParseQuery {
       this._explain = !!json.explain;
     }
 
+    if(json.comment) {
+      this._comment = json.comment;
+    }
+
     for (const key in json) {
       if (json.hasOwnProperty(key)) {
         if (
@@ -569,6 +579,7 @@ class ParseQuery {
             'subqueryReadPreference',
             'hint',
             'explain',
+            'comment',
           ].indexOf(key) === -1
         ) {
           this._extraOptions[key] = json[key];
@@ -2111,6 +2122,25 @@ class ParseQuery {
       this._xhrRequest.onchange();
     };
   }
+
+  /**
+   * Sets a comment to the query so that the query
+   *can be identified when using a the profiler for MongoDB.
+   *
+   * @param {string} value a comment can make your profile data easier to interpret and trace.
+   * @returns {Parse.Query} Returns the query, so you can chain this call.
+   */
+  comment(value: string): ParseQuery {
+    if (value == null) {
+      delete this._comment;
+      return this;
+    }
+    if (typeof value !== 'string') {
+      throw new Error('The value of a comment to be sent with this query must be a string.');
+    }
+    this._comment = value;
+    return this;
+  }
 }
 
 const DefaultController = {

src/__tests__/ParseQuery-test.js

@@ -3824,4 +3824,52 @@ describe('ParseQuery LocalDatastore', () => {
     expect(subscription.sessionToken).toBe('r:test');
     expect(subscription.query).toEqual(query);
   });
+
+  it('can add comment to query', () => {
+    const query = new ParseQuery('TestObject');
+    const comment = 'Hello Parse';
+    query.comment(comment);
+    expect(query.toJSON()).toEqual({
+      where: {},
+      comment: comment,
+    });
+  });
+
+  it('can add comment to query from json', () => {
+    const query = new ParseQuery('Item');
+    const comment = 'Hello Parse';
+    query.comment(comment);
+    const json = query.toJSON();
+    expect(json).toEqual({
+      where: {},
+      comment: comment,
+    });
+    const query2 = new ParseQuery('Item');
+    query2.withJSON(json);
+    expect(query2._comment).toEqual(comment);
+  });
+
+  it('comment can only be string', () => {
+    const obj1 = {
+      className: 'Item',
+      objectId: 'objectId1',
+      password: 123,
+      number: 3,
+      string: 'a',
+    };
+    const query = new ParseQuery('TestObject');
+    expect(query.comment.bind(query, obj1)).toThrow(
+      'The value of a comment to be sent with this query must be a string.'
+    );
+  });
+
+  it('clear comment when no value passed', () => {
+    const query = new ParseQuery('Item');
+    const comment = 'Hello Parse';
+    query.comment(comment);
+    expect(query._comment).toBe(comment);
+    query.comment();
+    expect(query._comment).toBeUndefined();
+  });
+
 });

types/ParseQuery.d.ts

@@ -18,6 +18,7 @@ type QueryJSON = {
     readPreference?: string;
     includeReadPreference?: string;
     subqueryReadPreference?: string;
+    comment?: string,
 };
 export default ParseQuery;
 /**
@@ -140,6 +141,7 @@ declare class ParseQuery {
     _hint: mixed;
     _explain: boolean;
     _xhrRequest: any;
+    _comment: string;
     /**
      * Adds constraint that at least one of the passed in queries matches.
      *
@@ -915,6 +917,14 @@ declare class ParseQuery {
      */
     cancel(): ParseQuery;
     _setRequestTask(options: any): void;
+    /**
+     * Sets a comment to the query so that the query 
+     * can be identified when using a the profiler for MongoDB.
+     *
+     * @param {string} value a comment can make your profile data easier to interpret and trace.
+     * @returns {Parse.Query} Returns the query, so you can chain this call.
+     */
+    comment(value: string): ParseQuery;
 }
 import { FullOptions } from './RESTController';
 import ParseObject from './ParseObject';