Add json() handler for Response (#55)

* Add json() handler for Response

* do not rethrow the error

* Attach json parser to Response directly

* Use indexOf to test header

* Fix typo

Author: fralonra

lib/response.js

@@ -108,6 +108,14 @@ function generatePayload (response) {
   res.body = res.payload
   res.trailers = response._lightMyRequest.trailers
 
+  // Prepare payload parsers
+  res.json = function parseJsonPayload () {
+    if (this.headers['content-type'].indexOf('application/json') < 0) {
+      throw new Error('The content-type of the response is not application/json')
+    }
+    return JSON.parse(this.payload)
+  }
+
   return res
 }
 

test/test.js

@@ -909,6 +909,58 @@ test('Should throw if both path and url are missing', (t) => {
   }
 })
 
+test('Response.json() should parse the JSON payload', (t) => {
+  t.plan(2)
+
+  const json = {
+    a: 1,
+    b: '2'
+  }
+
+  const dispatch = function (req, res) {
+    res.writeHead(200, { 'Content-Type': 'application/json' })
+    res.end(JSON.stringify(json))
+  }
+
+  inject(dispatch, { method: 'GET', path: 'http://example.com:8080/hello' }, (err, res) => {
+    t.error(err)
+    t.deepEqual(res.json(), json)
+  })
+})
+
+test('Response.json() should throw an error if content-type is not application/json', (t) => {
+  t.plan(2)
+
+  const json = {
+    a: 1,
+    b: '2'
+  }
+
+  const dispatch = function (req, res) {
+    res.writeHead(200, { 'Content-Type': 'text/plain' })
+    res.end(JSON.stringify(json))
+  }
+
+  inject(dispatch, { method: 'GET', path: 'http://example.com:8080/hello' }, (err, res) => {
+    t.error(err)
+    t.throws(res.json, Error)
+  })
+})
+
+test('Response.json() should throw an error if the payload is not of valid JSON format', (t) => {
+  t.plan(2)
+
+  const dispatch = function (req, res) {
+    res.writeHead(200, { 'Content-Type': 'application/json' })
+    res.end('notAJSON')
+  }
+
+  inject(dispatch, { method: 'GET', path: 'http://example.com:8080/hello' }, (err, res) => {
+    t.error(err)
+    t.throws(res.json, Error)
+  })
+})
+
 function getTestStream (encoding) {
   const word = 'hi'
   let i = 0