chore: Extract error handler and graphql instance to seperate files

packages/backend/src/app.ts

@@ -3,12 +3,10 @@ import createError from 'http-errors';
 import express, { Request, Response, NextFunction } from 'express';
 import cors from 'cors';
 import corsOptions from './config/cors-options';
-import { graphqlHTTP } from 'express-graphql';
+import graphQLInstance from './helpers/graphql-instance';
 import logger from './helpers/logger';
 import morgan from './helpers/morgan';
-
-import rootResolver from './graphql/root-resolver'
-import graphQLSchema from './graphql/graphql-schema'
+import errorHandler from './helpers/error-handler'
 
 const app = express();
 const port = appConfig.port;
@@ -16,32 +14,15 @@ const port = appConfig.port;
 app.use(morgan);
 app.use(express.json());
 app.use(express.urlencoded({ extended: false }));
-
 app.use(cors(corsOptions))
-
-app.use(
-  '/graphql',
-  graphqlHTTP({
-    schema: graphQLSchema,
-    rootValue: rootResolver,
-    graphiql: true,
-  }),
-);
+app.use('/graphql', graphQLInstance);
 
 // catch 404 and forward to error handler
 app.use(function(req: Request, res: Response, next: NextFunction) {
   next(createError(404));
 });
 
-// error handler
-app.use(function(err: any, req: Request, res: Response, _next: NextFunction) {
-  if(err.message === 'Not Found') {
-    res.status(404).end()
-  } else {
-    logger.error(err.message)
-    res.status(500).end()
-  }
-});
+app.use(errorHandler);
 
 app.listen(port, () => {
   logger.info(`Server is listening on ${port}`)

packages/backend/src/helpers/error-handler.ts

@@ -0,0 +1,13 @@
+import { Request, Response, NextFunction } from 'express';
+import logger from './logger';
+
+const errorHandler = (err: any, req: Request, res: Response, _next: NextFunction) => {
+  if(err.message === 'Not Found') {
+    res.status(404).end()
+  } else {
+    logger.error(err.message)
+    res.status(500).end()
+  }
+}
+
+export default errorHandler;

packages/backend/src/helpers/graphql-instance.ts

@@ -0,0 +1,11 @@
+import { graphqlHTTP } from 'express-graphql';
+import rootResolver from '../graphql/root-resolver'
+import graphQLSchema from '../graphql/graphql-schema'
+
+const graphQLInstance = graphqlHTTP({
+  schema: graphQLSchema,
+  rootValue: rootResolver,
+  graphiql: true,
+})
+
+export default graphQLInstance;