fix: Explain queries should always return as an array of results

integration/test/ParseQueryTest.js

@@ -2361,13 +2361,16 @@ describe('Parse Query', () => {
     const explain = await query.find();
     let indexName = '';
     // https://www.mongodb.com/docs/manual/reference/explain-results/#std-label-queryPlanner
-    const plan = explain.queryPlanner.winningPlan;
+    const plan = explain[0].queryPlanner.winningPlan;
     if (plan.inputStage) {
       indexName = plan.inputStage.inputStage.indexName;
     } else {
       indexName = plan.queryPlan.inputStage.inputStage.indexName;
     }
     assert.equal(indexName, '_id_');
+
+    const explainFirst = await query.first();
+    assert.equal(explainFirst.queryPlanner.winningPlan.inputStage.inputStage.indexName, '_id_');
   });
 
   it('can query with select on null field', async () => {

src/ParseQuery.js

@@ -896,6 +896,10 @@ class ParseQuery {
       if (!objects[0]) {
         return undefined;
       }
+      // Return generic object when explain is used
+      if (this._explain) {
+        return objects[0];
+      }
       if (!objects[0].className) {
         objects[0].className = this.className;
       }

src/__tests__/ParseQuery-test.js

@@ -1319,6 +1319,14 @@ describe('ParseQuery', () => {
     q.explain();
     q.equalTo('size', 'small')
       .find()
+      .then(results => {
+        expect(results[0].objectId).toBe('I1');
+        expect(results[0].size).toBe('small');
+        expect(results[0].name).toEqual('Product 3');
+        done();
+      });
+    q.equalTo('size', 'small')
+      .first()
       .then(result => {
         expect(result.objectId).toBe('I1');
         expect(result.size).toBe('small');