handle null in queries via knex's whereNull family of calls

Author: Mike Eldridge

src/index.js

@@ -336,9 +336,17 @@ class DSSqlAdapter {
           }
 
           if (op === '==' || op === '===') {
-            query = query.where(field, v)
+            if (v === null) {
+              query = query.whereNull(field)
+            } else {
+              query = query.where(field, v)
+            }
           } else if (op === '!=' || op === '!==') {
-            query = query.where(field, '!=', v)
+            if (v === null) {
+              query = query.whereNotNull(field)
+            } else {
+              query = query.where(field, '!=', v)
+            }
           } else if (op === '>') {
             query = query.where(field, '>', v)
           } else if (op === '>=') {
@@ -397,9 +405,17 @@ class DSSqlAdapter {
           } else if (op === 'like') {
             query = query.where(field, 'like', v)
           } else if (op === '|==' || op === '|===') {
-            query = query.orWhere(field, v)
+            if (v === null) {
+              query = query.orWhereNull(field)
+            } else {
+              query = query.orWhere(field, v)
+            }
           } else if (op === '|!=' || op === '|!==') {
-            query = query.orWhere(field, '!=', v)
+            if (v === null) {
+              query = query.orWhereNotNull(field)
+            } else {
+              query = query.orWhere(field, '!=', v)
+            }
           } else if (op === '|>') {
             query = query.orWhere(field, '>', v)
           } else if (op === '|>=') {

test/filterQuery.spec.js

@@ -34,4 +34,28 @@ describe('DSSqlAdapter#filterQuery', function () {
     var filterQuery = adapter.filterQuery(User, { orderBy: 'name' }, { query });
     assert.equal(filterQuery.toString(), 'select * from `test` order by `name` asc')
   });
+
+  it('should convert == null to IS NULL', function* () {
+    var query = adapter.query.from('test');
+    var filterQuery = adapter.filterQuery(User, { name: { '==' : null } }, { query });
+    assert.equal(filterQuery.toString(), 'select * from `test` where `name` is null')
+  });
+
+  it('should convert != null to IS NOT NULL', function* () {
+    var query = adapter.query.from('test');
+    var filterQuery = adapter.filterQuery(User, { name: { '!=' : null } }, { query });
+    assert.equal(filterQuery.toString(), 'select * from `test` where `name` is not null')
+  });
+
+  it('should convert |== null to OR field IS NULL', function* () {
+    var query = adapter.query.from('test');
+    var filterQuery = adapter.filterQuery(User, { name: 'Sean', age: { '|==' : null } }, { query });
+    assert.equal(filterQuery.toString(), 'select * from `test` where `name` = \'Sean\' or `age` is null')
+  });
+
+  it('should convert |!= null to OR field IS NOT NULL', function* () {
+    var query = adapter.query.from('test');
+    var filterQuery = adapter.filterQuery(User, { name: 'Sean', age: { '|!=' : null } }, { query });
+    assert.equal(filterQuery.toString(), 'select * from `test` where `name` = \'Sean\' or `age` is not null')
+  });
 });