✨ Support exists condition

Author: jysperm

README.md

@@ -8,7 +8,10 @@
 - [获取数据](#%E8%8E%B7%E5%8F%96%E6%95%B0%E6%8D%AE)
 - [查询条件](#%E6%9F%A5%E8%AF%A2%E6%9D%A1%E4%BB%B6)
   * [equalTo](#equalto)
+  * [exists](#exists)
   * [范围查询](#%E8%8C%83%E5%9B%B4%E6%9F%A5%E8%AF%A2)
+  * [数组查询](#%E6%95%B0%E7%BB%84%E6%9F%A5%E8%AF%A2)
+  * [组合查询](#%E7%BB%84%E5%90%88%E6%9F%A5%E8%AF%A2)
 - [关系查询](#%E5%85%B3%E7%B3%BB%E6%9F%A5%E8%AF%A2)
   * [Relation](#relation)
   * [Pointer](#pointer)
@@ -148,6 +151,18 @@ query {
 }
 ```
 
+### exists
+
+exists 可以用来查询存在或不存在某一字段的对象，例如我们查询存在 title 但不存在 content 的 Todo：
+
+```graphql
+query {
+  Todo(exists: {title: true, content: false}) {
+    title, content
+  }
+}
+```
+
 ### 范围查询
 
 ```graphql
@@ -180,6 +195,18 @@ query {
 - `containedIn` 约束指定列中包含特定元素。
 - `containsAll` 约束指定列中包含所有元素。
 
+### 组合查询
+
+你可以将我们前面提到的所有查询条件组合在一起：
+
+```graphql
+query {
+  Todo(exists: {content: true}, ascending: priority, greaterThan: {priority: 5}) {
+    title, content, priority
+  }
+}
+```
+
 ## 关系查询
 
 ### Relation

schema.js

@@ -176,6 +176,9 @@ module.exports = function buildSchema({appId, appKey, masterKey}) {
               },
               containsAll: {
                 type: createFieldsInputType('containsAll', new GraphQLList(GraphQLID))
+              },
+              exists: {
+                type: createFieldsInputType('exists', GraphQLBoolean)
               }
             },
             resolve: (source, args, {authOptions}, info) => {
@@ -187,17 +190,25 @@ module.exports = function buildSchema({appId, appKey, masterKey}) {
                 }
               });
 
-              ['equalTo', 'greaterThan', 'greaterThanOrEqualTo', 'lessThan', 'lessThanOrEqualTo',
-               'containedIn', 'containsAll'].forEach( method => {
+              ['equalTo', 'greaterThan', 'greaterThanOrEqualTo', 'lessThan',
+               'lessThanOrEqualTo', 'containedIn', 'containsAll'].forEach( method => {
                 if (_.isObject(args[method])) {
                   _.forEach(args[method], (value, key) => {
                     query[method](key, value);
                   });
-                } else {
-                  debug(`Ignored argument ${method}`);
                 }
               });
 
+              if (_.isObject(args.exists)) {
+                _.forEach(args.exists, (value, key) => {
+                  if (value) {
+                    query.exists(key);
+                  } else {
+                    query.doesNotExist(key);
+                  }
+                });
+              }
+
               if (args.objectId) {
                 query.equalTo('objectId', args.objectId);
               }

test/query.js

@@ -1,3 +1,5 @@
+const {expect} = require('chai');
+
 const requestGraphQL = require('./client');
 
 describe('query', function() {
@@ -98,4 +100,19 @@ describe('query', function() {
       });
     });
   });
+
+  it('should work with exists', () => {
+    return requestGraphQL(`
+      query {
+        Todo(exists: {title: true, content: false}) {
+          title, content
+        }
+      }
+    `).then( res => {
+      res.body.data.Todo.forEach( ({title, content}) => {
+        title.should.be.a('string');
+        expect(content).to.not.exist;
+      });
+    });
+  });
 });