diff --git a/src/__tests__/__testSchema__/mutation.auth/index.ts b/src/__tests__/__testSchema__/mutation.auth/index.ts
index d0b9a07..6e0c5cd 100644
--- a/src/__tests__/__testSchema__/mutation.auth/index.ts
+++ b/src/__tests__/__testSchema__/mutation.auth/index.ts
@@ -1,3 +1,5 @@
+import { NamespaceConfig } from '../../../typeDefs';
+
 export default {
   resolve: () => ({}),
-};
+} as NamespaceConfig;
diff --git a/src/__tests__/__testSchema__/mutation.auth/login.ts b/src/__tests__/__testSchema__/mutation.auth/login.ts
index 31f9db6..32f985d 100644
--- a/src/__tests__/__testSchema__/mutation.auth/login.ts
+++ b/src/__tests__/__testSchema__/mutation.auth/login.ts
@@ -1,6 +1,8 @@
+import { FieldConfig } from '../../../typeDefs';
+
 export default {
   type: 'Boolean',
   description: 'Login operation',
   args: { email: 'String', password: 'String' },
   resolve: () => true,
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/mutation.auth/logout.ts b/src/__tests__/__testSchema__/mutation.auth/logout.ts
index 598abfa..9b99175 100644
--- a/src/__tests__/__testSchema__/mutation.auth/logout.ts
+++ b/src/__tests__/__testSchema__/mutation.auth/logout.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../typeDefs';
+
 export default {
   type: 'Boolean',
   resolve: () => true,
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/mutation.auth/nested/method.ts b/src/__tests__/__testSchema__/mutation.auth/nested/method.ts
index 598abfa..edd2a78 100644
--- a/src/__tests__/__testSchema__/mutation.auth/nested/method.ts
+++ b/src/__tests__/__testSchema__/mutation.auth/nested/method.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../../typeDefs';
+
 export default {
   type: 'Boolean',
   resolve: () => true,
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/mutation.user/create.ts b/src/__tests__/__testSchema__/mutation.user/create.ts
index 598abfa..9b99175 100644
--- a/src/__tests__/__testSchema__/mutation.user/create.ts
+++ b/src/__tests__/__testSchema__/mutation.user/create.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../typeDefs';
+
 export default {
   type: 'Boolean',
   resolve: () => true,
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/mutation.user/update.ts b/src/__tests__/__testSchema__/mutation.user/update.ts
index 598abfa..9b99175 100644
--- a/src/__tests__/__testSchema__/mutation.user/update.ts
+++ b/src/__tests__/__testSchema__/mutation.user/update.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../typeDefs';
+
 export default {
   type: 'Boolean',
   resolve: () => true,
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/mutation/logs.nested/list.ts b/src/__tests__/__testSchema__/mutation/logs.nested/list.ts
index 598abfa..edd2a78 100644
--- a/src/__tests__/__testSchema__/mutation/logs.nested/list.ts
+++ b/src/__tests__/__testSchema__/mutation/logs.nested/list.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../../typeDefs';
+
 export default {
   type: 'Boolean',
   resolve: () => true,
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/query.auth/index.ts b/src/__tests__/__testSchema__/query.auth/index.ts
index d01e64a..3a81907 100644
--- a/src/__tests__/__testSchema__/query.auth/index.ts
+++ b/src/__tests__/__testSchema__/query.auth/index.ts
@@ -1,3 +1,5 @@
+import { NamespaceConfig } from '../../../typeDefs';
+
 export default {
   type: 'NamespaceCustomTypeName',
-};
+} as NamespaceConfig;
diff --git a/src/__tests__/__testSchema__/query.auth/isLoggedIn.ts b/src/__tests__/__testSchema__/query.auth/isLoggedIn.ts
index ed52f3d..87df801 100644
--- a/src/__tests__/__testSchema__/query.auth/isLoggedIn.ts
+++ b/src/__tests__/__testSchema__/query.auth/isLoggedIn.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../typeDefs';
+
 export default {
   type: (sc) => sc.get('Boolean'),
   resolve: () => true,
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/query.auth/nested/method.ts b/src/__tests__/__testSchema__/query.auth/nested/method.ts
index 598abfa..edd2a78 100644
--- a/src/__tests__/__testSchema__/query.auth/nested/method.ts
+++ b/src/__tests__/__testSchema__/query.auth/nested/method.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../../typeDefs';
+
 export default {
   type: 'Boolean',
   resolve: () => true,
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/query/__skip/field.ts b/src/__tests__/__testSchema__/query/__skip/field.ts
index 7218203..3120700 100644
--- a/src/__tests__/__testSchema__/query/__skip/field.ts
+++ b/src/__tests__/__testSchema__/query/__skip/field.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../../typeDefs';
+
 export default {
   type: 'String',
   resolve: () => 'text',
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/query/field.spec.ts b/src/__tests__/__testSchema__/query/field.spec.ts
index 1bdfc66..7b6a5e3 100644
--- a/src/__tests__/__testSchema__/query/field.spec.ts
+++ b/src/__tests__/__testSchema__/query/field.spec.ts
@@ -1,5 +1,7 @@
+import { FieldConfig } from '../../../typeDefs';
+
 export default {
   type: 'String',
   description: 'This file should be skipped',
   resolve: () => 'ok',
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/query/field.ts b/src/__tests__/__testSchema__/query/field.ts
index 5c618a2..427c8b8 100644
--- a/src/__tests__/__testSchema__/query/field.ts
+++ b/src/__tests__/__testSchema__/query/field.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../typeDefs';
+
 export default {
   type: 'String',
   resolve: () => 'ok',
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/query/index.ts b/src/__tests__/__testSchema__/query/index.ts
index d0b9a07..6e0c5cd 100644
--- a/src/__tests__/__testSchema__/query/index.ts
+++ b/src/__tests__/__testSchema__/query/index.ts
@@ -1,3 +1,5 @@
+import { NamespaceConfig } from '../../../typeDefs';
+
 export default {
   resolve: () => ({}),
-};
+} as NamespaceConfig;
diff --git a/src/__tests__/__testSchema__/query/me/address.city.ts b/src/__tests__/__testSchema__/query/me/address.city.ts
index 598abfa..edd2a78 100644
--- a/src/__tests__/__testSchema__/query/me/address.city.ts
+++ b/src/__tests__/__testSchema__/query/me/address.city.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../../typeDefs';
+
 export default {
   type: 'Boolean',
   resolve: () => true,
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/query/me/address.street.ts b/src/__tests__/__testSchema__/query/me/address.street.ts
index 598abfa..edd2a78 100644
--- a/src/__tests__/__testSchema__/query/me/address.street.ts
+++ b/src/__tests__/__testSchema__/query/me/address.street.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../../typeDefs';
+
 export default {
   type: 'Boolean',
   resolve: () => true,
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/query/me/index.ts b/src/__tests__/__testSchema__/query/me/index.ts
index a8c993b..97a3bc2 100644
--- a/src/__tests__/__testSchema__/query/me/index.ts
+++ b/src/__tests__/__testSchema__/query/me/index.ts
@@ -1,9 +1,11 @@
+import { NamespaceConfig } from '../../../../typeDefs';
+
 export default {
   args: {
     arg: 'Int',
   },
-  resolve: (_: any, __: any, context: any) => {
+  resolve: (_, __, context) => {
     if (!context?.isAdmin) throw new Error('You should be the ADMIN');
     return {};
   },
-};
+} as NamespaceConfig;
diff --git a/src/__tests__/__testSchema__/query/me/name.ts b/src/__tests__/__testSchema__/query/me/name.ts
index 0a2421f..199b483 100644
--- a/src/__tests__/__testSchema__/query/me/name.ts
+++ b/src/__tests__/__testSchema__/query/me/name.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../../typeDefs';
+
 export default {
   type: 'String',
   resolve: () => 'nodkz',
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/query/some.index.ts b/src/__tests__/__testSchema__/query/some.index.ts
index 8ced91d..df6b980 100644
--- a/src/__tests__/__testSchema__/query/some.index.ts
+++ b/src/__tests__/__testSchema__/query/some.index.ts
@@ -1,3 +1,5 @@
+import { FieldConfig } from '../../../typeDefs';
+
 export default {
   type: `
     type SomeIndexFileType {
@@ -5,4 +7,4 @@ export default {
     }
   `,
   resolve: () => ({ awesomeValue: 'awesomeValue' }),
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/query/some.nested.ts b/src/__tests__/__testSchema__/query/some.nested.ts
index 95140ad..a2b44ba 100644
--- a/src/__tests__/__testSchema__/query/some.nested.ts
+++ b/src/__tests__/__testSchema__/query/some.nested.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../typeDefs';
+
 export default {
   type: 'Int',
   resolve: () => 123,
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/query/user/extendedData.ts b/src/__tests__/__testSchema__/query/user/extendedData.ts
index d4064ae..d663bb3 100644
--- a/src/__tests__/__testSchema__/query/user/extendedData.ts
+++ b/src/__tests__/__testSchema__/query/user/extendedData.ts
@@ -1,3 +1,5 @@
+import { FieldConfig } from '../../../../typeDefs';
+
 export default {
   type: `
     type UserExtendedData {
@@ -5,4 +7,4 @@ export default {
     }
   `,
   resolve: () => ({ starsCount: 10 }),
-};
+} as FieldConfig;
diff --git a/src/__tests__/__testSchema__/query/user/index.ts b/src/__tests__/__testSchema__/query/user/index.ts
index a93b517..282a40e 100644
--- a/src/__tests__/__testSchema__/query/user/index.ts
+++ b/src/__tests__/__testSchema__/query/user/index.ts
@@ -1,3 +1,5 @@
+import { NamespaceConfig } from '../../../../typeDefs';
+
 export default {
   type: `
     type UserAwesomeType {
@@ -12,4 +14,4 @@ export default {
       lastName: 'User',
     };
   },
-};
+} as NamespaceConfig;
diff --git a/src/__tests__/__testSchema__/query/user/roles.ts b/src/__tests__/__testSchema__/query/user/roles.ts
index 1753d30..9863766 100644
--- a/src/__tests__/__testSchema__/query/user/roles.ts
+++ b/src/__tests__/__testSchema__/query/user/roles.ts
@@ -1,4 +1,6 @@
+import { FieldConfig } from '../../../../typeDefs';
+
 export default {
   type: ['String'],
   resolve: () => ['ADMIN', 'USER'],
-};
+} as FieldConfig;
diff --git a/src/__tests__/astVisitor-test.ts b/src/__tests__/astVisitor-test.ts
index 6673716..43f144e 100644
--- a/src/__tests__/astVisitor-test.ts
+++ b/src/__tests__/astVisitor-test.ts
@@ -177,10 +177,10 @@ describe('astVisitor', () => {
         }
       },
       FILE: (node) => {
-        const currentResolve = node.code.default.resolve;
+        const currentResolve = node.code.default?.resolve;
         if (currentResolve) {
-          const description = node.code.default.description;
-          node.code.default.resolve = (s: any, a: any, c: any, i: any) => {
+          const description = node.code.default?.description;
+          (node.code as any).default.resolve = (s: any, a: any, c: any, i: any) => {
             logs.push({
               description,
               args: a,
diff --git a/src/astToSchema.ts b/src/astToSchema.ts
index 01d2c06..2ae9f29 100644
--- a/src/astToSchema.ts
+++ b/src/astToSchema.ts
@@ -8,10 +8,12 @@ import {
   isComposeOutputType,
   isSomeOutputTypeDefinitionString,
   inspect,
+  isFunction,
 } from 'graphql-compose';
 import { AstRootNode, AstRootTypeNode, AstDirNode, AstFileNode } from './directoryToAst';
 import dedent from 'dedent';
 import { GraphQLObjectType } from 'graphql';
+import { FieldConfig, NamespaceConfig } from './typeDefs';
 
 export interface AstToSchemaOptions {
   schemaComposer?: SchemaComposer<any>;
@@ -29,7 +31,7 @@ export function astToSchema<TContext = any>(
     if (!opts.schemaComposer) {
       throw new Error(dedent`
         Provided option 'schemaComposer' should be an instance of SchemaComposer class from 'graphql-compose' package. 
-        Recieved:
+        Received:
           ${inspect(opts.schemaComposer)}
       `);
     }
@@ -77,7 +79,7 @@ export function createFields(
 
   if (ast.kind === 'file') {
     parent.addNestedFields({
-      [name]: prepareFieldConfig(sc, ast),
+      [name]: prepareFieldConfig(sc, ast) as FieldConfig,
     });
     return;
   }
@@ -190,8 +192,8 @@ function prepareNamespaceFieldConfig(
 function prepareFieldConfig(
   sc: SchemaComposer<any>,
   ast: AstFileNode
-): ObjectTypeComposerFieldConfig<any, any> {
-  const fc = ast.code.default as any;
+): FieldConfig | NamespaceConfig {
+  const fc = ast.code.default;
 
   if (!fc) {
     throw new Error(dedent`
diff --git a/src/astVisitor.ts b/src/astVisitor.ts
index 714be71..671b605 100644
--- a/src/astVisitor.ts
+++ b/src/astVisitor.ts
@@ -57,7 +57,7 @@ export function visitNode(
   node: AstDirNode | AstFileNode | AstRootTypeNode,
   visitor: AstVisitor,
   info: VisitInfo
-) {
+): void {
   let result: VisitorEmptyResult | AstDirNode | AstFileNode | AstRootTypeNode;
   if (node.kind === 'dir') {
     if (visitor.DIR) result = visitor.DIR(node, info);
diff --git a/src/directoryToAst.ts b/src/directoryToAst.ts
index ab23425..11c4070 100644
--- a/src/directoryToAst.ts
+++ b/src/directoryToAst.ts
@@ -1,5 +1,6 @@
 import fs from 'fs';
 import { join, resolve, dirname, basename } from 'path';
+import { FieldConfig, NamespaceConfig } from './typeDefs';
 
 export interface DirectoryToAstOptions {
   relativePath?: string;
@@ -35,7 +36,7 @@ export interface AstDirNode extends AstBaseNode {
 export interface AstFileNode extends AstBaseNode {
   kind: 'file';
   code: {
-    default?: any;
+    default?: FieldConfig | NamespaceConfig;
   };
 }
 
diff --git a/src/index.ts b/src/index.ts
index fb6e1d3..0a16acc 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,13 +1,18 @@
 import { directoryToAst, DirectoryToAstOptions } from './directoryToAst';
 import { astToSchema, AstToSchemaOptions } from './astToSchema';
+import { SchemaComposer } from 'graphql-compose';
+import { GraphQLSchema } from 'graphql';
 
 export interface BuildOptions extends DirectoryToAstOptions, AstToSchemaOptions {}
 
-export function buildSchema(module: NodeModule, opts: BuildOptions = {}) {
+export function buildSchema(module: NodeModule, opts: BuildOptions = {}): GraphQLSchema {
   return loadSchemaComposer(module, opts).buildSchema();
 }
 
-export function loadSchemaComposer(module: NodeModule, opts: BuildOptions) {
+export function loadSchemaComposer<TContext = any>(
+  module: NodeModule,
+  opts: BuildOptions
+): SchemaComposer<TContext> {
   const ast = directoryToAst(module, opts);
   const sc = astToSchema(ast, opts);
   return sc;
@@ -25,6 +30,7 @@ export {
 } from './directoryToAst';
 export { astToSchema, AstToSchemaOptions } from './astToSchema';
 export * from './testHelpers';
+export * from './typeDefs';
 
 export {
   astVisitor,
diff --git a/src/testHelpers.ts b/src/testHelpers.ts
index 48d8d1e..edf17f3 100644
--- a/src/testHelpers.ts
+++ b/src/testHelpers.ts
@@ -128,7 +128,7 @@ export function testSDL(opts: {
   fc: ObjectTypeComposerFieldConfigAsObjectDefinition<any, any, any> | Resolver;
   schemaComposer?: SchemaComposer<any>;
   deep?: boolean;
-}) {
+}): string {
   const sc = opts.schemaComposer || new SchemaComposer();
   sc.Query.setField(FIELD, opts.fc);
   sc.buildSchema();
diff --git a/src/typeDefs.ts b/src/typeDefs.ts
new file mode 100644
index 0000000..4d969ab
--- /dev/null
+++ b/src/typeDefs.ts
@@ -0,0 +1,8 @@
+import { ObjectTypeComposerFieldConfigAsObjectDefinition } from 'graphql-compose';
+
+export type FieldConfig<TContext = any, TArgs = any, TSource = any> =
+  ObjectTypeComposerFieldConfigAsObjectDefinition<TSource, TContext, TArgs>;
+
+export type NamespaceConfig<TContext = any, TArgs = any, TSource = any> = Partial<
+  ObjectTypeComposerFieldConfigAsObjectDefinition<TSource, TContext, TArgs>
+>;