fix: include referenced model as null when no rows are matched

to stay consistent with `Query.prototype.fetch` et al

Author: Joel Mukuthu

lib/KnormRelations.js

@@ -249,19 +249,25 @@ class KnormRelations {
 
         if (this.options.joins) {
           this.options.joins.forEach(join => {
+            const as = join.options.as;
+
+            if (join.options.first && parsedRow[as] !== undefined) {
+              return;
+            }
+
             const data = join.parseRow(
               row,
               Object.assign({ isNested: true }, options)
             );
-            if (data) {
-              const as = join.options.as;
-              if (join.options.first) {
-                if (!parsedRow[as]) {
-                  parsedRow[as] = data;
-                }
-              } else {
+
+            if (join.options.first) {
+              parsedRow[as] = data;
+            } else {
+              if (data) {
                 parsedRow[as] = parsedRow[as] || [];
                 parsedRow[as].push(data);
+              } else if (!parsedRow[as]) {
+                parsedRow[as] = data;
               }
             }
           });
@@ -279,6 +285,7 @@ class KnormRelations {
 
         if (this.options.joins) {
           const parsedRows = Object.values(this.parsedRows);
+          // this is needed for `distinct` without an `id` column
           if (parsedRows.length) {
             rows = parsedRows;
           }

test/KnormRelations.spec.js

@@ -257,7 +257,7 @@ describe('KnormRelations', () => {
                     name: 'User 1',
                     image: [new Image({ id: 1, userId: 1, categoryId: 1 })]
                   }),
-                  new User({ name: 'User 2' })
+                  new User({ name: 'User 2', image: null })
                 ]
               )
           );
@@ -306,7 +306,7 @@ describe('KnormRelations', () => {
                 name: 'User 1',
                 image: [new Image({ id: 1 })]
               }),
-              new User({ id: 2, name: 'User 2' })
+              new User({ id: 2, name: 'User 2', image: null })
             ]
           );
         });
@@ -326,20 +326,21 @@ describe('KnormRelations', () => {
               new User({
                 id: 2,
                 name: 'User 2',
-                confirmed: true
+                confirmed: true,
+                image: null
               })
             ]
           );
         });
 
-        it('does not include the joined model if no rows were matched', async () => {
+        it('includes the joined model as `null` if no rows were matched', async () => {
           const query = new Query(User)
             .leftJoin(new Query(Image))
             .where({ id: 2 });
           await expect(
             query.fetch(),
             'to be fulfilled with sorted rows satisfying',
-            [new User({ id: 2, name: 'User 2' })]
+            [new User({ id: 2, name: 'User 2', image: null })]
           );
         });
 
@@ -461,7 +462,7 @@ describe('KnormRelations', () => {
           await expect(
             query.fetch(),
             'to be fulfilled with sorted rows satisfying',
-            [{ messages: undefined }, { messages: undefined }]
+            [{ messages: null }, { messages: null }]
           );
         });
 
@@ -772,9 +773,8 @@ describe('KnormRelations', () => {
 
             await expect(
               query.fetch(),
-              // TODO: hmmmmmmm
               'to be fulfilled with sorted rows exhaustively satisfying',
-              [{ image: undefined }]
+              [{ image: null }]
             );
           });