feat(scopes): allow scope `group`s to be concatenated (#7957)

lib/model.js

@@ -1351,7 +1351,7 @@ class Model {
         _.assignWith(self._scope, scope, (objectValue, sourceValue, key) => {
           if (key === 'where') {
             return Array.isArray(sourceValue) ? sourceValue : _.assign(objectValue || {}, sourceValue);
-          } else if (['attributes', 'include'].indexOf(key) >= 0 && Array.isArray(objectValue) && Array.isArray(sourceValue)) {
+          } else if (['attributes', 'include', 'group'].indexOf(key) >= 0 && Array.isArray(objectValue) && Array.isArray(sourceValue)) {
             return objectValue.concat(sourceValue);
           }
 

test/unit/model/scope.test.js

@@ -41,6 +41,13 @@ describe(Support.getTestDialectTeaser('Model'), () => {
     projects: {
       include: [Project]
     },
+    groupByCompanyId: {
+      group: ['company.id']
+    },
+    groupByProjectId: {
+      group: ['project.id'],
+      include: [Project]
+    },
     noArgs() {
       // This does not make much sense, since it does not actually need to be in a function,
       // In reality it could be used to do for example new Date or random in the scope - but we want it deterministic
@@ -215,6 +222,13 @@ describe(Support.getTestDialectTeaser('Model'), () => {
         Company.scope('doesntexist');
       }).to.throw('Invalid scope doesntexist called.');
     });
+
+    it('should concatenate scope groups', () => {
+      expect(Company.scope('groupByCompanyId', 'groupByProjectId')._scope).to.deep.equal({
+        group: ['company.id', 'project.id'],
+        include: [{ model: Project }]
+      });
+    });
   });
 
   describe('addScope', () => {