fix(mongoose): mock query result on collection level

Unmock `Query.prototype.exec` and mock collection methods instead.

Fixes #218

packages/casl-mongoose/spec/.eslintrc

@@ -0,0 +1,14 @@
+{
+  "env": {
+    "jest": true
+  },
+  "globals": {
+    "expect": true,
+    "spy": true
+  },
+  "rules": {
+    "semi": ["error", "never"],
+    "no-use-before-define": "off",
+    "no-unused-expressions": "off"
+  }
+}

packages/casl-mongoose/spec/accessible_records.spec.js

@@ -1,4 +1,4 @@
-import { AbilityBuilder, Ability } from '@casl/ability'
+import { AbilityBuilder } from '@casl/ability'
 import mongoose from 'mongoose'
 import { accessibleRecordsPlugin, toMongoQuery } from '../src'
 
@@ -33,7 +33,7 @@ describe('Accessible Records Plugin', () => {
 
   describe('`accessibleBy` method', () => {
     beforeEach(() => {
-      ability = AbilityBuilder.define(can => {
+      ability = AbilityBuilder.define((can) => {
         can('read', 'Post', { state: 'draft' })
         can('update', 'Post', { state: 'published' })
       })
@@ -77,7 +77,6 @@ describe('Accessible Records Plugin', () => {
       let query
 
       beforeEach(() => {
-        Post.Query.prototype.exec = spy(() => Promise.resolve('original `exec` method call'))
         query = Post.find().accessibleBy(ability, 'notAllowedAction')
       })
 
@@ -128,7 +127,8 @@ describe('Accessible Records Plugin', () => {
       })
 
       it('calls original `exec` for other cases', async () => {
-        await query.update({ $set: { state: 'draft' } }).exec()
+        Post.Query.prototype.exec = spy(() => Promise.resolve('original `exec` method call'))
+        await query.update({ $set: { state: 'draft' } })
 
         expect(Post.Query.prototype.exec).to.have.been.called()
       })

packages/casl-mongoose/src/accessible_records.js

@@ -1,33 +1,30 @@
 import { toMongoQuery } from './mongo';
 
+const DENY_CONDITION_NAME = '__forbiddenByCasl__';
+
+function returnQueryResult(original, returnValue, ...args) {
+  const [conditions, , callback] = args;
+
+  if (conditions[DENY_CONDITION_NAME]) {
+    return typeof callback === 'function'
+      ? callback(null, returnValue)
+      : Promise.resolve(returnValue);
+  }
+
+  if (conditions.hasOwnProperty(DENY_CONDITION_NAME)) {
+    delete conditions[DENY_CONDITION_NAME];
+  }
+
+  return original.apply(this, args);
+}
+
 function emptyQuery(query) {
-  const originalExec = query.exec;
-
-  query.where({ __forbiddenByCasl__: 1 });
-  query.exec = function exec(operation, callback) {
-    const op = typeof operation === 'string' ? operation : this.op;
-    const cb = typeof operation === 'function' ? operation : callback;
-    let value;
-
-    if (op.indexOf('findOne') === 0) {
-      value = null;
-    } else if (op.indexOf('find') === 0) {
-      value = [];
-    } else if (op === 'count') {
-      value = 0;
-    } else {
-      return originalExec.call(this, operation, callback);
-    }
-
-    return Promise.resolve(value)
-      .then((v) => {
-        if (typeof cb === 'function') {
-          cb(null, v);
-        }
-
-        return v;
-      });
-  };
+  query.where({ [DENY_CONDITION_NAME]: 1 });
+  const collection = Object.create(query._collection) // eslint-disable-line
+  query._collection = collection // eslint-disable-line
+  collection.find = returnQueryResult.bind(collection, collection.find, []);
+  collection.findOne = returnQueryResult.bind(collection, collection.findOne, null);
+  collection.count = returnQueryResult.bind(collection, collection.count, 0);
 
   return query;
 }