Support condition objects in utility functions #6666 (#6685)

https://github.com/sequelize/sequelize/issues/6666

Makes it possible to pass condition objects (e.g. {foo: 'bar'}) to Sequelize.fn(), Sequelize.cast().
This makes it easy to use conditional counts in Sequelize queries, e.g.

Sequelize.fn('sum', {name: 'Fred'}) which results in SUM(`name` = 'Fred') which can be used in attribute definition
to count entities for which the condition matches.

changelog.md

@@ -14,6 +14,7 @@
 - [ADDED] `options.rowFormat` added to Query Generator for MySQL dialect using InnoDB engines [#6824] (https://github.com/sequelize/sequelize/issues/6824)
 - [FIXED] `Increment` / `Decrement` properly maps to timestamp fields [#6296](https://github.com/sequelize/sequelize/issues/6296)
 - [FIXED] Issue with overrriding custom methods with association mixins (all association methods are now exposed) [#6682](https://github.com/sequelize/sequelize/issues/6682)
+- [ADDED] Support condition objects in utility functions [#6685](https://github.com/sequelize/sequelize/pull/6685)
 
 ## BC breaks:
 - `DATEONLY` now returns string in `YYYY-MM-DD` format rather than `Date` type

docs/api/sequelize.md

@@ -861,6 +861,16 @@ instance.updateAttributes({
 })
 ```
 
+Alternatively, a condition object can be used as an argument e.g. to get the count of rows for which the predicate evaluates to true. Works on mysql and sqlite.
+```js
+sequelize.fn('sum', { age: { $gt: 25 }, name: 'Joe' })
+```
+
+An explicit cast is required on postgres.
+```js
+sequelize.fn('sum', sequelize.cast({ age: { $gt: 25 }, name: 'Joe' }, 'int'))
+```
+
 **See:**
 
 * [Model#find](model#find)
@@ -874,7 +884,7 @@ instance.updateAttributes({
 | Name | Type | Description |
 | ---- | ---- | ----------- |
 | fn | String | The function you want to call |
-| args | any | All further arguments will be passed as arguments to the function |
+| args | any | All further arguments will be passed as arguments to the function. An argument may be a condition object. |
 
 
 ***

lib/dialects/abstract/query-generator.js

@@ -1698,6 +1698,8 @@ const QueryGenerator = {
     } else if (smth instanceof Utils.Cast) {
       if (smth.val._isSequelizeMethod) {
         result = this.handleSequelizeMethod(smth.val, tableName, factory, options, prepend);
+      } else if (_.isPlainObject(smth.val)) {
+        result = this.whereItemsQuery(smth.val);
       } else {
         result = this.escape(smth.val);
       }
@@ -1707,6 +1709,8 @@ const QueryGenerator = {
       result = smth.fn + '(' + smth.args.map(arg => {
         if (arg._isSequelizeMethod) {
           return this.handleSequelizeMethod(arg, tableName, factory, options, prepend);
+        } else if (_.isPlainObject(arg)) {
+          return this.whereItemsQuery(arg);
         } else {
           return this.escape(arg);
         }

test/integration/utils.test.js

@@ -5,7 +5,9 @@
 var chai = require('chai')
   , expect = chai.expect
   , Utils = require(__dirname + '/../../lib/utils')
-  , Support = require(__dirname + '/support');
+  , Support = require(__dirname + '/support')
+  , DataTypes = require(__dirname + '/../../lib/data-types')
+  , Sequelize = require('../../index');
 
 describe(Support.getTestDialectTeaser('Utils'), function() {
   describe('removeCommentsFromFunctionString', function() {
@@ -226,4 +228,82 @@ describe(Support.getTestDialectTeaser('Utils'), function() {
       expect(Utils.singularize('status')).to.equal('status');
     });
   });
+
+  describe('Sequelize.fn', function() {
+    var Airplane;
+
+    beforeEach(function() {
+      Airplane = this.sequelize.define('Airplane', {
+        wings: DataTypes.INTEGER,
+        engines: DataTypes.INTEGER
+      });
+
+      return Airplane.sync({ force: true }).then(function () {
+        return Airplane.bulkCreate([
+          {
+            wings: 2,
+            engines: 0
+          }, {
+            wings: 4,
+            engines: 1
+          }, {
+            wings: 2,
+            engines: 2
+          }
+        ]);
+      });
+    });
+
+    if (Support.getTestDialect() !== 'mssql') {
+      it('accepts condition object (with cast)', function() {
+        const type = (Support.getTestDialect() === 'mysql') ? 'unsigned': 'int';
+
+        return Airplane.findAll({
+          attributes: [
+            [this.sequelize.fn('COUNT', '*'), 'count'],
+            [Sequelize.fn('SUM', Sequelize.cast({
+              engines: 1
+          }, type)), 'count-engines'],
+            [Sequelize.fn('SUM', Sequelize.cast({
+              $or: {
+                engines: {
+                  $gt: 1
+                },
+                wings: 4
+              }
+          }, type)), 'count-engines-wings']
+          ]
+        }).spread(function (airplane) {
+          expect(parseInt(airplane.get('count'))).to.equal(3);
+          expect(parseInt(airplane.get('count-engines'))).to.equal(1);
+          expect(parseInt(airplane.get('count-engines-wings'))).to.equal(2);
+        });
+      });
+    }
+
+    if (Support.getTestDialect() !== 'mssql' && Support.getTestDialect() !== 'postgres') {
+      it('accepts condition object (auto casting)', function() {
+        return Airplane.findAll({
+          attributes: [
+          [this.sequelize.fn('COUNT', '*'), 'count'],
+          [Sequelize.fn('SUM', {
+            engines: 1
+          }), 'count-engines'],
+          [Sequelize.fn('SUM', {
+            $or: {
+              engines: {
+                $gt: 1
+              },
+              wings: 4
+            }
+          }), 'count-engines-wings']
+          ]
+        }).spread(function (airplane) {
+          expect(parseInt(airplane.get('count'))).to.equal(3);
+          expect(parseInt(airplane.get('count-engines'))).to.equal(1);
+          expect(parseInt(airplane.get('count-engines-wings'))).to.equal(2);
+        });
+      });
+    }
+  });
 });

test/unit/utils.test.js

@@ -4,7 +4,8 @@ var chai = require('chai')
   , expect = chai.expect
   , Support   = require(__dirname + '/support')
   , DataTypes = require(__dirname + '/../../lib/data-types')
-  , Utils     = require(__dirname + '/../../lib/utils');
+  , Utils     = require(__dirname + '/../../lib/utils')
+  , Support   = require(__dirname + '/../support');
 
 // Notice: [] will be replaced by dialect specific tick/quote character when there is not dialect specific expectation but only a default expectation
 
@@ -456,4 +457,23 @@ suite(Support.getTestDialectTeaser('Utils'), function() {
       expect(stack[3].getFunctionName()).to.eql('this_here_test');
     });
   });
+
+  suite('Sequelize.cast', function() {
+    var sql = Support.sequelize;
+    var generator = sql.queryInterface.QueryGenerator;
+    var run = generator.handleSequelizeMethod.bind(generator);
+    var expectsql = Support.expectsql;
+
+    test('accepts condition object (auto casting)', function fn() {
+      expectsql(run(sql.fn('SUM', sql.cast({
+        $or: {
+          foo: 'foo',
+          bar: 'bar'
+        }
+      }, 'int'))), {
+        default: 'SUM(CAST(([foo] = \'foo\' OR [bar] = \'bar\') AS INT))',
+        mssql: 'SUM(CAST(([foo] = N\'foo\' OR [bar] = N\'bar\') AS INT))'
+      });
+    });
+});
 });