diff --git a/package.json b/package.json
index 6c1588b..d69c254 100644
--- a/package.json
+++ b/package.json
@@ -29,7 +29,7 @@
   ],
   "dependencies": {
     "graphql-relay": "^0.3.6",
-    "lodash": "^4.0.0"
+    "lodash": "^4.0.1"
   },
   "peerDependencies": {
     "graphql": "^0.4.14",
@@ -37,7 +37,7 @@
   },
   "devDependencies": {
     "babel": "^6.3.26",
-    "babel-cli": "^6.4.0",
+    "babel-cli": "^6.4.5",
     "babel-eslint": "^5.0.0-beta6",
     "babel-istanbul": "^0.6.0",
     "babel-polyfill": "^6.3.14",
@@ -47,12 +47,12 @@
     "chai": "^3.4.1",
     "chai-subset": "^1.2.0",
     "eslint": "^1.10.3",
-    "eslint-config-airbnb": "^3.1.0",
+    "eslint-config-airbnb": "^4.0.0",
     "graphql": "^0.4.14",
-    "mocha": "^2.3.4",
-    "mongoose": "^4.3.6",
+    "mocha": "^2.4.2",
+    "mongoose": "^4.3.7",
     "pre-commit": "^1.1.2",
-    "sinon": "^1.17.2",
+    "sinon": "^1.17.3",
     "sinon-chai": "^2.8.0"
   },
   "pre-commit": [
diff --git a/src/e2e.spec.js b/src/e2e.spec.js
index 284b18f..9c3a392 100644
--- a/src/e2e.spec.js
+++ b/src/e2e.spec.js
@@ -11,7 +11,7 @@ describe('e2e', () => {
     let user2;
     let schema;
     let hooks;
-    before(function beforeAll() {
+    before(() => {
       hooks = {
         viewer: {
           pre: spy(),
diff --git a/src/model/model.js b/src/model/model.js
index df009f5..bc6cd03 100644
--- a/src/model/model.js
+++ b/src/model/model.js
@@ -98,9 +98,9 @@ function extractPath(schemaPath) {
  * @return {Object) extractedSchemaPaths
  */
 function extractPaths(schemaPaths, model) {
-  return reduce(schemaPaths, (fields, schemaPath) => {
-    return merge(fields, extractPath(schemaPath, model));
-  }, {});
+  return reduce(schemaPaths, (fields, schemaPath) => (
+    merge(fields, extractPath(schemaPath, model))
+  ), {});
 }
 
 /**
diff --git a/src/query/query.js b/src/query/query.js
index 57cc377..6d1a237 100644
--- a/src/query/query.js
+++ b/src/query/query.js
@@ -95,12 +95,10 @@ function updateOne(Collection, {id, _id, ...args}, info) {
 function deleteOne(Collection, args) {
   const _id = processId(args);
 
-  return Collection.remove({_id}).then(({result}) => {
-    return {
-      id: toGlobalId(Collection.modelName, _id),
-      ok: !!result.ok
-    };
-  });
+  return Collection.remove({_id}).then(({result}) => ({
+    id: toGlobalId(Collection.modelName, _id),
+    ok: !!result.ok
+  }));
 }
 
 function getList(Collection, selector, options = {}, info = null) {
@@ -113,14 +111,12 @@ function getList(Collection, selector, options = {}, info = null) {
   }
 
   const projection = getFieldList(info);
-  return Collection.find(selector, projection, options).then((result) => {
-    return result.map((value) => {
-      return {
-        ...value.toObject(),
-        _type: Collection.modelName
-      };
-    });
-  });
+  return Collection.find(selector, projection, options).then((result) => (
+    result.map((value) => ({
+      ...value.toObject(),
+      _type: Collection.modelName
+    }))
+  ));
 }
 
 function getOneResolver(graffitiModel) {
@@ -303,12 +299,10 @@ async function connectionFromModel(graffitiModel, args, info) {
     return emptyConnection();
   }
 
-  const edges = result.map((value) => {
-    return {
-      cursor: idToCursor(value._id),
-      node: value
-    };
-  });
+  const edges = result.map((value) => ({
+    cursor: idToCursor(value._id),
+    node: value
+  }));
 
   const firstElement = await getFirst(Collection);
   return {
diff --git a/src/query/query.spec.js b/src/query/query.spec.js
index f758fff..cfced50 100644
--- a/src/query/query.spec.js
+++ b/src/query/query.spec.js
@@ -44,9 +44,7 @@ describe('query', () => {
       model: {
         modelName: type,
         findById(id) {
-          const obj = objArray.find((obj) => {
-            return obj._id === id;
-          });
+          const obj = objArray.find((obj) => obj._id === id);
           return Promise.resolve(obj);
         },
 
@@ -126,12 +124,10 @@ describe('query', () => {
   describe('connectionFromModel', () => {
     it('should return a connection', async function connectionFromModelTest() {
       const result = await connectionFromModel(graffitiModels.type, {});
-      const edges = resultArray.map((obj) => {
-        return {
-          cursor: _idToCursor(obj._id),
-          node: obj
-        };
-      });
+      const edges = resultArray.map((obj) => ({
+        cursor: _idToCursor(obj._id),
+        node: obj
+      }));
       const startCursor = edges[0].cursor;
       const endCursor = edges[edges.length - 1].cursor;
       expect(result).to.containSubset({
diff --git a/src/schema/schema.spec.js b/src/schema/schema.spec.js
index a7efdb3..4198340 100644
--- a/src/schema/schema.spec.js
+++ b/src/schema/schema.spec.js
@@ -36,8 +36,8 @@ describe('schema', () => {
 
   describe('getQueryField', () => {
     it('should return a singular and a plural query field', function getQueryFieldTest() {
-      this.sandbox.stub(query, 'getOneResolver').returns(() => {});
-      this.sandbox.stub(query, 'getListResolver').returns(() => {});
+      this.sandbox.stub(query, 'getOneResolver').returns(() => null);
+      this.sandbox.stub(query, 'getListResolver').returns(() => null);
 
       const graphQLType = types.Qux;
       const fields = getQueryField({Qux: {model: {}}}, graphQLType);
@@ -65,8 +65,8 @@ describe('schema', () => {
 
   describe('getMutationField', () => {
     it('should return an addXyz and an updateXyz field', function getMutationFieldTest() {
-      this.sandbox.stub(query, 'getAddOneMutateHandler').returns(() => {});
-      this.sandbox.stub(query, 'getUpdateOneMutateHandler').returns(() => {});
+      this.sandbox.stub(query, 'getAddOneMutateHandler').returns(() => null);
+      this.sandbox.stub(query, 'getUpdateOneMutateHandler').returns(() => null);
       const graphQLType = types.Qux;
       const fields = getMutationField({Qux: {model: {}}}, graphQLType);
       const args = {
@@ -147,14 +147,14 @@ describe('schema', () => {
       this.sandbox.stub(type, 'getTypes').returns(types);
     });
 
-    it('should return a GraphQL schema', function getSchemaTest() {
+    it('should return a GraphQL schema', () => {
       const schema = getSchema({});
       expect(schema).instanceOf(GraphQLSchema);
       expect(schema._queryType.name).to.be.equal('RootQuery');
       expect(schema._mutationType.name).to.be.equal('RootMutation');
     });
 
-    it('should return a GraphQL schema without mutations', function getSchemaTest() {
+    it('should return a GraphQL schema without mutations', () => {
       const schema = getSchema({}, {mutation: false});
       expect(schema).instanceOf(GraphQLSchema);
       expect(schema._queryType.name).to.be.equal('RootQuery');
diff --git a/src/type/custom/buffer.js b/src/type/custom/buffer.js
index ccafc73..cd26a42 100644
--- a/src/type/custom/buffer.js
+++ b/src/type/custom/buffer.js
@@ -16,7 +16,7 @@ export default new GraphQLScalarType({
   parseValue: coerceBuffer,
   parseLiteral(ast) {
     if (ast.kind !== Kind.STRING) {
-      throw new GraphQLError('Query error: Can only parse strings to buffers but got a: ' + ast.kind, [ast]);
+      throw new GraphQLError(`Query error: Can only parse strings to buffers but got a: ${ast.kind}`, [ast]);
     }
 
     const result = new Buffer(ast.value);
diff --git a/src/type/custom/buffer.spec.js b/src/type/custom/buffer.spec.js
index 059191c..336f4a0 100644
--- a/src/type/custom/buffer.spec.js
+++ b/src/type/custom/buffer.spec.js
@@ -73,9 +73,7 @@ describe('GraphQL buffer type', () => {
                 type: GraphQLBuffer
               }
             },
-            resolve: (_, {bar}) => {
-              return new Buffer(bar.toString() + '-qux');
-            }
+            resolve: (_, {bar}) => new Buffer(`${bar.toString()}-qux`)
           }
         }
       })
diff --git a/src/type/custom/date.js b/src/type/custom/date.js
index c13c875..606d2eb 100644
--- a/src/type/custom/date.js
+++ b/src/type/custom/date.js
@@ -26,7 +26,7 @@ export default new GraphQLScalarType({
   },
   parseLiteral(ast) {
     if (ast.kind !== Kind.STRING) {
-      throw new GraphQLError('Query error: Can only parse strings to dates but got a: ' + ast.kind, [ast]);
+      throw new GraphQLError(`Query error: Can only parse strings to buffers but got a: ${ast.kind}`, [ast]);
     }
 
     const result = new Date(ast.value);
diff --git a/src/type/custom/date.spec.js b/src/type/custom/date.spec.js
index fe806a3..c1cc2f1 100644
--- a/src/type/custom/date.spec.js
+++ b/src/type/custom/date.spec.js
@@ -103,9 +103,7 @@ describe('GraphQL date type', () => {
                 type: GraphQlDate
               }
             },
-            resolve: (_, {date}) => {
-              return new Date(date.getTime() + 24 * 3600 * 1000);
-            }
+            resolve: (_, {date}) => new Date(date.getTime() + 24 * 3600 * 1000)
           }
         }
       })
diff --git a/src/type/custom/generic.js b/src/type/custom/generic.js
index 53848a5..23046d6 100644
--- a/src/type/custom/generic.js
+++ b/src/type/custom/generic.js
@@ -12,7 +12,7 @@ export default new GraphQLScalarType({
   parseValue: coerceDate,
   parseLiteral(ast) {
     if (ast.kind !== Kind.STRING) {
-      throw new GraphQLError('Query error: Can only parse strings to JSON but got a: ' + ast.kind, [ast]);
+      throw new GraphQLError(`Query error: Can only parse strings to buffers but got a: ${ast.kind}`, [ast]);
     }
 
     const json = ast.value.replace(/\'/g, '"');
diff --git a/src/type/custom/generic.spec.js b/src/type/custom/generic.spec.js
index 56de8f2..1e9d58a 100644
--- a/src/type/custom/generic.spec.js
+++ b/src/type/custom/generic.spec.js
@@ -79,9 +79,7 @@ describe('GraphQL generic type', () => {
                 type: GraphQLGeneric
               }
             },
-            resolve: (_, {bar}) => {
-              return new Unknown(bar.field + '-qux');
-            }
+            resolve: (_, {bar}) => new Unknown(`${bar.field}-qux`)
           }
         }
       })
diff --git a/src/type/type.js b/src/type/type.js
index aee5682..7bf3c40 100644
--- a/src/type/type.js
+++ b/src/type/type.js
@@ -39,10 +39,10 @@ function addType(name, type) {
 }
 
 // Node interface
-const {nodeInterface} = nodeDefinitions(null, (obj) => {
+const {nodeInterface} = nodeDefinitions(null, (obj) => (
   // Type resolver
-  return obj._type ? types[obj._type] : null;
-});
+  obj._type ? types[obj._type] : null
+));
 
 // GraphQL Viewer type
 const GraphQLViewer = new GraphQLObjectType({
@@ -245,9 +245,7 @@ export default function getType(graffitiModels, {name, description, fields}, pat
     }
 
     if (!graphQLField.resolve) {
-      graphQLField.resolve = addHooks((source) => {
-        return source[name];
-      }, hooks);
+      graphQLField.resolve = addHooks((source) => source[name], hooks);
     }
 
     graphQLFields[name] = graphQLField;
diff --git a/src/utils/Middleware.js b/src/utils/Middleware.js
index b753102..07ed740 100644
--- a/src/utils/Middleware.js
+++ b/src/utils/Middleware.js
@@ -48,6 +48,6 @@ export default class Middleware {
         await fn.call(this, next, ...result);
         return lastResult;
       };
-    }, () => {})();
+    }, () => null)();
   }
 }