Added $modifyEager query param to filter relation based on relation's field

Author: Dekel Barzilay

README.md

@@ -147,7 +147,7 @@ Note that all this eager related options are optional.
   object or array of objects with the following properties:
   - `expression` - the relation expression that the filter will be applied.
   - `filter` - the filter function. It uses
-    [`filterEager`](https://vincit.github.io/objection.js/api/query-builder/eager-methods.html#filtereager)
+    [`modifyEager`](https://vincit.github.io/objection.js/api/query-builder/eager-methods.html#modifyeager)
     internally.
 - **`namedEagerFilters`** - object containing named eager filter functions.
   Filter is opt-in via `$eager` parameter.
@@ -164,6 +164,8 @@ Note that all this eager related options are optional.
   `JoinEagerAlgorithm`. See
   [`$joinEager`](https://vincit.github.io/objection.js/api/query-builder/eager-methods.html#joineager)
   documentation.
+- **`$modifyEager`** - filter relation based on a relation's field.
+  e.g. `companies.find({ query: { $eager: 'employees', $modifyEager: { employees: { name: 'John' } } } })`
 - **`$pick`** - pick properties from result models. See
   [`pick`](https://vincit.github.io/objection.js/api/query-builder/other-methods.html#pick) documentation.
 

package-lock.json

@@ -1,7 +1,7 @@
 {
   "name": "feathers-objection",
   "description": "A service plugin for ObjectionJS an ORM based on KnexJS",
-  "version": "4.5.2",
+  "version": "4.6.0",
   "homepage": "https://github.com/feathersjs-ecosystem/feathers-objection",
   "keywords": [
     "feathers",

package.json

@@ -160,6 +160,7 @@ class Service extends AdapterService {
     if (params.$eager) { delete params.$eager; }
     if (params.$joinEager) { delete params.$joinEager; }
     if (params.$joinRelation) { delete params.$joinRelation; }
+    if (params.$modifyEager) { delete params.$modifyEager; }
     if (params.$pick) { delete params.$pick; }
     if (params.$noSelect) { delete params.$noSelect; }
 
@@ -267,7 +268,6 @@ class Service extends AdapterService {
     }
 
     // $eager for Objection eager queries
-
     if (query && query.$eager) {
       q.eager(query.$eager, this.namedEagerFilters);
       delete query.$eager;
@@ -290,14 +290,23 @@ class Service extends AdapterService {
 
     // apply eager filters if specified
     if (this.eagerFilters) {
-      const eagerFilters = this.eagerFilters;
-      if (Array.isArray(eagerFilters)) {
-        for (const eagerFilter of eagerFilters) {
-          q.filterEager(eagerFilter.expression, eagerFilter.filter);
-        }
-      } else {
-        q.filterEager(eagerFilters.expression, eagerFilters.filter);
+      const eagerFilters = Array.isArray(this.eagerFilters) ? this.eagerFilters : [this.eagerFilters];
+
+      for (const eagerFilter of eagerFilters) {
+        q.modifyEager(eagerFilter.expression, eagerFilter.filter);
+      }
+    }
+
+    if (query && query.$modifyEager) {
+      for (const eagerFilterExpression of Object.keys(query.$modifyEager)) {
+        const eagerFilterQuery = query.$modifyEager[eagerFilterExpression];
+
+        q.modifyEager(eagerFilterExpression, builder => {
+          this.objectify(builder, eagerFilterQuery);
+        });
       }
+
+      delete query.$modifyEager;
     }
 
     if (query && query.$pick) {

src/index.js

@@ -134,7 +134,7 @@ const app = feathers()
       model: Company,
       id: 'id',
       multi: ['create', 'remove', 'patch'],
-      whitelist: ['$eager', '$pick', '$between', '$notBetween', '$containsKey', '$contains', '$contained', '$any', '$all', '$noSelect', '$like'],
+      whitelist: ['$eager', '$modifyEager', '$pick', '$between', '$notBetween', '$containsKey', '$contains', '$contained', '$any', '$all', '$noSelect', '$like'],
       allowedEager: '[ceos, clients]',
       namedEagerFilters: {
         notSnoop (builder) {
@@ -721,26 +721,52 @@ describe('Feathers Objection Service', () => {
   });
 
   describe('Eager queries', () => {
-    beforeEach(async () => {
-      const data = await people
+    const ids = {};
+
+    before(async () => {
+      ids.ceo = await people
         .create({
           name: 'Snoop',
           age: 20
         });
 
-      await companies
+      ids.companies = await companies
         .create([
           {
             name: 'Google',
-            ceo: data.id
+            ceo: ids.ceo.id
           },
           {
             name: 'Apple',
-            ceo: data.id
+            ceo: ids.ceo.id
+          }
+        ]);
+
+      ids.employees = await employees
+        .create([
+          {
+            name: 'John',
+            companyId: 1
+          },
+          {
+            name: 'John',
+            companyId: 1
+          },
+          {
+            name: 'Dan',
+            companyId: 1
           }
         ]);
     });
 
+    after(async () => {
+      await people.remove(ids.ceo.id);
+
+      for (const company of ids.companies) { await companies.remove(company.id); }
+
+      for (const employee of ids.employees) { await employees.remove(employee.id); }
+    });
+
     it('allows eager queries', () => {
       return companies.find({ query: { $eager: 'ceos' } }).then(data => {
         expect(data[0].ceos).to.be.ok;
@@ -753,6 +779,13 @@ describe('Feathers Objection Service', () => {
       });
     });
 
+    it('allows modifyEager queries', () => {
+      return companies.find({ query: { $eager: 'employees', $modifyEager: { employees: { name: 'John' } } }, mergeAllowEager: 'employees' }).then(data => {
+        expect(data[0].employees.length).to.equal(2);
+        expect(data[1].employees.length).to.equal(0);
+      });
+    });
+
     it('allows eager queries with pick', () => {
       return companies.find({ query: { $eager: 'ceos', $pick: ['ceos'] } }).then(data => {
         expect(data[0].ceos).to.be.ok;