feat: Simplifies error handling. (#5)

BREAKING CHANGE: `errorCatcher` removed from `FactoryConfig` in favour of `handleTransaction`.

Author: ryasmi

package-lock.json

@@ -26,7 +26,8 @@
   },
   "dependencies": {
     "@js-entity-repos/core": "^6.0.2",
-    "http-status-codes": "^1.3.0"
+    "http-status-codes": "^1.3.0",
+    "uuid": "^3.2.1"
   },
   "devDependencies": {
     "@ht2-labs/semantic-release": "1.0.31",
@@ -37,6 +38,7 @@
     "@types/express": "4.11.1",
     "@types/mocha": "2.2.48",
     "@types/source-map-support": "0.4.0",
+    "@types/uuid": "3.4.3",
     "assert-rejects": "0.1.1",
     "axios": "0.18.0",
     "dotenv": "5.0.1",

package.json

@@ -33,12 +33,17 @@ const todosFacade = factory<TodoEntity>({
   },
   // Optional property.
   defaultPaginationLimit: 10,
-  // Optional property that catches errors from handlers.
-  errorCatcher: (handler) => (req, res) => {
-    handler(req, res).catch((err) => {
-      res.status(500).send();
-    });
-  },
+  // Optional property to handle transactions.
+  handleTransaction: async ({ req, res }, handler) => {
+    // The transactionId allow items found in logs to be matched with responses to users.
+    const transactionId = uuid();
+    try {
+      await handler({ transactionId });
+    } catch (err) {
+      console.error({ err, req, res, transactionId})
+      res.status(500).send(transactionId);
+    }
+  };
   service,
 });
 ```

readme.md

@@ -1,11 +1,11 @@
 import Facade from '@js-entity-repos/core/dist/Facade';
 import Entity from '@js-entity-repos/core/dist/types/Entity';
 import Filter from '@js-entity-repos/core/dist/types/Filter';
-import ErrorCatcher from './utils/ErrorCatcher';
+import TransactionHandler from './utils/TransactionHandler';
 
 export default interface FacadeConfig<E extends Entity> {
   readonly constructFilter: (filter: Filter<E>) => any;
   readonly service: Facade<E>;
-  readonly errorCatcher: ErrorCatcher;
+  readonly handleTransaction: TransactionHandler;
   readonly defaultPaginationLimit: number;
 }

src/FacadeConfig.ts

@@ -1,11 +1,11 @@
 import Facade from '@js-entity-repos/core/dist/Facade';
 import Entity from '@js-entity-repos/core/dist/types/Entity';
 import { Filter } from '@js-entity-repos/core/dist/types/Filter';
-import ErrorCatcher from './utils/ErrorCatcher';
+import TransactionHandler from './utils/TransactionHandler';
 
 export default interface FactoryConfig<E extends Entity> {
   readonly constructFilter?: (filter: Filter<E>) => any;
   readonly service: Facade<E>;
-  readonly errorCatcher?: ErrorCatcher;
+  readonly handleTransaction?: TransactionHandler;
   readonly defaultPaginationLimit?: number;
 }

src/FactoryConfig.ts

@@ -11,13 +11,13 @@ import patchEntities from './functions/patchEntities';
 import removeEntities from './functions/removeEntities';
 import removeEntity from './functions/removeEntity';
 import replaceEntity from './functions/replaceEntity';
-import catchErrors from './utils/catchErrors';
+import handleTransaction from './utils/handleTransaction';
 
 export default <E extends Entity>(factoryConfig: FactoryConfig<E>): Router => {
   const facadeConfig: FacadeConfig<E> = {
     constructFilter: (filter) => filter,
     defaultPaginationLimit: 10,
-    errorCatcher: catchErrors,
+    handleTransaction,
     ...factoryConfig,
   };
   const router = Router();

src/factory.ts

@@ -2,14 +2,15 @@ import Entity from '@js-entity-repos/core/dist/types/Entity';
 import { Request, Response } from 'express';
 import { OK } from 'http-status-codes';
 import FacadeConfig from '../FacadeConfig';
-import catchErrors from '../utils/catchErrors';
 import getJsonQueryParam from '../utils/getJsonQueryParam';
 
 export default <E extends Entity>(config: FacadeConfig<E>) => {
-  return catchErrors(async (req: Request, res: Response) => {
-    const { count } = await config.service.countEntities({
-      filter: config.constructFilter(getJsonQueryParam(req.query, 'filter')),
+  return async (req: Request, res: Response) => {
+    await config.handleTransaction({ req, res }, async () => {
+      const { count } = await config.service.countEntities({
+        filter: config.constructFilter(getJsonQueryParam(req.query, 'filter')),
+      });
+      res.status(OK).json(count);
     });
-    res.status(OK).json(count);
-  });
+  };
 };

src/functions/countEntities.ts

@@ -2,14 +2,15 @@ import Entity from '@js-entity-repos/core/dist/types/Entity';
 import { Request, Response } from 'express';
 import { OK } from 'http-status-codes';
 import FacadeConfig from '../FacadeConfig';
-import catchErrors from '../utils/catchErrors';
 
 export default <E extends Entity>(config: FacadeConfig<E>) => {
-  return catchErrors(async (req: Request, res: Response) => {
-    const { entity } = await config.service.createEntity({
-      entity: req.body,
-      id: req.body.id,
+  return async (req: Request, res: Response) => {
+    await config.handleTransaction({ req, res }, async () => {
+      const { entity } = await config.service.createEntity({
+        entity: req.body,
+        id: req.body.id,
+      });
+      res.status(OK).json(entity);
     });
-    res.status(OK).json(entity);
-  });
+  };
 };

src/functions/createEntity.ts

@@ -2,29 +2,30 @@ import Entity from '@js-entity-repos/core/dist/types/Entity';
 import { Request, Response } from 'express';
 import { OK } from 'http-status-codes';
 import FacadeConfig from '../FacadeConfig';
-import catchErrors from '../utils/catchErrors';
 import getJsonQueryParam from '../utils/getJsonQueryParam';
 import getNumberQueryParam from '../utils/getNumberQueryParam';
 
 export default <E extends Entity>(config: FacadeConfig<E>) => {
-  return catchErrors(async (req: Request, res: Response) => {
-    const limit = getNumberQueryParam(req.query, 'limit', config.defaultPaginationLimit);
-    const result = await config.service.getEntities({
-      filter: config.constructFilter(getJsonQueryParam(req.query, 'filter')),
-      pagination: {
-        cursor: req.query.cursor,
-        forward: req.query.forward === 'true',
-        limit,
-      },
-      sort: getJsonQueryParam(req.query, 'sort'),
+  return async (req: Request, res: Response) => {
+    await config.handleTransaction({ req, res }, async () => {
+      const limit = getNumberQueryParam(req.query, 'limit', config.defaultPaginationLimit);
+      const result = await config.service.getEntities({
+        filter: config.constructFilter(getJsonQueryParam(req.query, 'filter')),
+        pagination: {
+          cursor: req.query.cursor,
+          forward: req.query.forward === 'true',
+          limit,
+        },
+        sort: getJsonQueryParam(req.query, 'sort'),
+      });
+      res.status(OK);
+      if (result.nextCursor !== undefined) {
+        res.setHeader('x-entities-next-cursor', result.nextCursor);
+      }
+      if (result.previousCursor !== undefined) {
+        res.setHeader('x-entities-previous-cursor', result.previousCursor);
+      }
+      res.json(result.entities);
     });
-    res.status(OK);
-    if (result.nextCursor !== undefined) {
-      res.setHeader('x-entities-next-cursor', result.nextCursor);
-    }
-    if (result.previousCursor !== undefined) {
-      res.setHeader('x-entities-previous-cursor', result.previousCursor);
-    }
-    res.json(result.entities);
-  });
+  };
 };

src/functions/getEntities.ts

@@ -2,15 +2,16 @@ import Entity from '@js-entity-repos/core/dist/types/Entity';
 import { Request, Response } from 'express';
 import { OK } from 'http-status-codes';
 import FacadeConfig from '../FacadeConfig';
-import catchErrors from '../utils/catchErrors';
 import getJsonQueryParam from '../utils/getJsonQueryParam';
 
 export default <E extends Entity>(config: FacadeConfig<E>) => {
-  return catchErrors(async (req: Request, res: Response) => {
-    const { entity } = await config.service.getEntity({
-      filter: config.constructFilter(getJsonQueryParam(req.query, 'filter')),
-      id: req.params.id,
+  return async (req: Request, res: Response) => {
+    await config.handleTransaction({ req, res }, async () => {
+      const { entity } = await config.service.getEntity({
+        filter: config.constructFilter(getJsonQueryParam(req.query, 'filter')),
+        id: req.params.id,
+      });
+      res.status(OK).json(entity);
     });
-    res.status(OK).json(entity);
-  });
+  };
 };