middy - npm Package Compare versions

Comparing version 0.2.18 to 0.3.0

package.json

 {
   "name": "middy",
-  "version": "0.2.18",
+  "version": "0.3.0",
   "description": "The simple (but cool 😎) middleware engine for AWS lambda in Node.js",
@@ -35,2 +35,4 @@ "main": "src/index.js",
   "devDependencies": {
+    "babel-jest": "^21.2.0",
+    "babel-preset-env": "^1.6.1",
     "codecov": "^3.0.0",
@@ -46,3 +48,4 @@ "eslint": "^4.4.1",
     "jsdoc": "^3.5.5",
-    "jsdoc-to-markdown": "^3.0.0"
+    "jsdoc-to-markdown": "^3.0.0",
+    "regenerator-runtime": "^0.11.0"
   },
@@ -49,0 +52,0 @@ "dependencies": {

README.md

@@ -26,12 +26,14 @@ <div align="center">
   </a>
+  <a href="https://greenkeeper.io/">
+    <img src="https://badges.greenkeeper.io/middyjs/middy.svg" alt="Greenkeeper badge"  style="max-width:100%;">
+  </a>
   <a href="https://gitter.im/middyjs">
     <img src="https://badges.gitter.im/gitterHQ/gitter.svg" alt="Chat on Gitter"  style="max-width:100%;">
   </a>
-  <a href="https://greenkeeper.io/">
-    <img src="https://badges.greenkeeper.io/middyjs/middy.svg" alt="Greenkeeper badge"  style="max-width:100%;">
-  </a>
 </p>
 </div>
 
+
 ## TOC
+
  - [A little appetizer](#a-little-appetizer)
@@ -251,2 +253,41 @@ - [Install](#install)
 
+### Async Middlewares
+
+Middy supports middlewares that return promises instead that directly calling the callback:
+
+```javascript
+const asyncValidator = () => {
+  before: (handler) => {
+    if (handler.event.body) {
+      return new Promise((resolve, reject) => {
+        // async validation logic
+      })
+    }
+
+    return Promise.resolve()
+  }
+}
+
+handler.use(asyncValidator())
+```
+
+Thanks to this behaviour you can define middlewares using `async` functions:
+
+```javascript
+const asyncValidator = () => {
+  before: async (handler) => {
+    if (handler.event.body) {
+      return await asyncValidate(handler.event.body)
+    }
+
+    return
+  }
+}
+
+handler.use(asyncValidator())
+```
+
+Of course, since AWS lambda runs on Node.js 6.10, you will need to transpile your `async/await` code (e.g. using [babel](https://babeljs.io/)).
+
+
 ## Writing a middleware
@@ -445,3 +486,3 @@
 | onError | [<code>middlewareAttachFunction</code>](#middlewareAttachFunction) | attach a new *error-handler-only* middleware |
-| __middlewares | <code>Object</code> | contains the list of all the attached    middlewares organised by type (`before`, `after`, `onError`). To be used only   for testing and debugging purposes |
+| __middlewares | <code>Object</code> | contains the list of all the attached   middlewares organised by type (`before`, `after`, `onError`). To be used only   for testing and debugging purposes |
 
@@ -448,0 +489,0 @@ <a name="useFunction"></a>

src/__tests__/middy.js

@@ -407,2 +407,105 @@ const middy = require('../middy')
   })
+
+  test('It should handle async middlewares', (endTest) => {
+    const asyncBefore = async (handler) => {
+      handler.event.asyncBefore = true
+    }
+
+    const asyncAfter = async (handler) => {
+      handler.event.asyncAfter = true
+    }
+
+    const handler = middy((event, context, callback) => {
+      return callback(null, {some: 'response'})
+    })
+
+    handler
+      .before(asyncBefore)
+      .after(asyncAfter)
+
+    handler({}, {}, (err, response) => {
+      expect(err).toBe(null)
+      expect(handler.event.asyncBefore).toBeTruthy()
+      expect(handler.event.asyncAfter).toBeTruthy()
+      endTest()
+    })
+  })
+
+  test('It should handle async error middlewares', (endTest) => {
+    const expectedError = new Error('Error in handler')
+
+    const asyncOnError = async (handler) => {
+      handler.error = null
+      handler.response = {result: 'The error is handled'}
+    }
+
+    const handler = middy((event, context, callback) => {
+      return callback(expectedError)
+    })
+
+    handler
+      .onError(asyncOnError)
+
+    handler({}, {}, (err, response) => {
+      expect(err).toBe(null)
+      expect(response).toEqual({result: 'The error is handled'})
+      endTest()
+    })
+  })
+
+  test('A middleware that return a non-promise should trigger an error', (endTest) => {
+    const beforeMiddleware = (handler) => {
+      return 'this is not a promise'
+    }
+
+    const handler = middy((event, context, callback) => {
+      return callback(null, {foo: 'bar'})
+    })
+
+    handler
+      .before(beforeMiddleware)
+
+    handler({}, {}, (err, response) => {
+      expect(err.message).toBe('Unexpected return value in middleware')
+      endTest()
+    })
+  })
+
+  test('An error middleware that return a non-promise should trigger an error', (endTest) => {
+    const onErrorMiddleware = (handler) => {
+      return 'this is not a promise'
+    }
+
+    const handler = middy((event, context, callback) => {
+      throw new Error('something happened')
+    })
+
+    handler
+      .onError(onErrorMiddleware)
+
+    handler({}, {}, (err, response) => {
+      expect(err.message).toBe('Unexpected return value in onError middleware')
+      expect(err.originalError.message).toBe('something happened')
+      endTest()
+    })
+  })
+
+  // see issue #49 (https://github.com/middyjs/middy/issues/49)
+  test('Handles error thrown in async functions', (endTest) => {
+    const beforeMiddleware = async (handler) => {
+      throw new Error('I am throwing in an async func')
+    }
+
+    const handler = middy((event, context, callback) => {
+      return callback(null, {foo: 'bar'})
+    })
+
+    handler
+      .before(beforeMiddleware)
+
+    handler({}, {}, (err, response) => {
+      expect(err.message).toBe('I am throwing in an async func')
+      endTest()
+    })
+  })
 })

src/middy.js

@@ -0,1 +1,3 @@
+const isPromise = require('./isPromise')
+
 /**
@@ -11,3 +13,3 @@ * @typedef middy
  * @property {middlewareAttachFunction} onError - attach a new *error-handler-only* middleware
- * @property {Object} __middlewares - contains the list of all the attached 
+ * @property {Object} __middlewares - contains the list of all the attached
  *   middlewares organised by type (`before`, `after`, `onError`). To be used only
@@ -59,3 +61,15 @@ *   for testing and debugging purposes
       if (nextMiddleware) {
-        return nextMiddleware(instance, runNext)
+        const retVal = nextMiddleware(instance, runNext)
+
+        if (retVal) {
+          if (!isPromise(retVal)) {
+            throw new Error('Unexpected return value in middleware')
+          }
+
+          retVal
+            .then(runNext)
+            .catch(done)
+        }
+
+        return
       }
@@ -84,3 +98,18 @@
       if (nextMiddleware) {
-        return nextMiddleware(instance, runNext)
+        const retVal = nextMiddleware(instance, runNext)
+
+        if (retVal) {
+          if (!isPromise(retVal)) {
+            const invalidMiddlewareReturnError = new Error('Unexpected return value in onError middleware')
+            // embed original error to avoid swallowing the real exception
+            invalidMiddlewareReturnError.originalError = err
+            throw invalidMiddlewareReturnError
+          }
+
+          retVal
+            .then(runNext)
+            .catch(done)
+        }
+
+        return
       }
@@ -87,0 +116,0 @@

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Found 1 instance in 1 package

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Improved metrics

Total package byte prevSize

321296

increased by40.8%

Number of package files

34

increased by9.68%

Lines of code

8475

increased by45.29%

Number of lines in readme file

536

increased by8.28%

Worsened metrics

Dev dependency count

14

increased by27.27%

No dependency changes