Do not use it for `json()` either

lib/server.js

@@ -5,26 +5,25 @@ const server = require('http').Server
 const getRawBody = require('raw-body')
 const typer = require('media-typer')
 const isStream = require('isstream')
+const Q = require('q')
 
 const DEV = process.env.NODE_ENV === 'development'
 const TESTING = process.env.NODE_ENV === 'test'
 
-const serve = fn => server((req, res) => {
-  run(req, res, fn)
-})
+const serve = fn => server(Q.async(function * (req, res) {
+  yield exports.run(req, res, fn)
+}))
 
 module.exports = exports = serve
 
-exports.json = json
 exports.send = send
 exports.sendError = sendError
 exports.createError = createError
 
-async function run(req, res, fn) {
+exports.run = Q.async(function * (req, res, fn) {
   try {
-    const val = await fn(req, res)
+    const val = yield fn(req, res)
 
-    // Return 204 No Content if value is null
     if (val === null) {
       send(res, 204, null)
     }
@@ -34,55 +33,47 @@ async function run(req, res, fn) {
       send(res, res.statusCode || 200, val)
     }
   } catch (err) {
-    await sendError(req, res, err)
-  }
-}
-
-exports.run = (req, res, fn) => {
-  fn(req, res).then(val => {
-    // Return 204 No Content if value is null
-    if (val === null) {
-      send(res, 204, null)
-    }
-
-    // Return a undefined-null value -> send
-    if (undefined !== val) {
-      send(res, res.statusCode || 200, val)
-    }
-  }).catch(err => {
     sendError(req, res, err)
-  })
-}
+  }
+})
 
 // maps requests to buffered raw bodies so that
 // multiple calls to `json` work as expected
 const rawBodyMap = new WeakMap()
 
-async function json(req, {limit = '1mb'} = {}) {
+const returnJSON = (resolve, reject, str) => {
   try {
-    const type = req.headers['content-type']
-    const length = req.headers['content-length']
-    const encoding = typer.parse(type).parameters.charset
-
-    let str = rawBodyMap.get(req)
-    if (!str) {
-      str = await getRawBody(req, {limit, length, encoding})
-      rawBodyMap.set(req, str)
-    }
-
-    try {
-      return JSON.parse(str)
-    } catch (err) {
-      throw createError(400, 'Invalid JSON', err)
-    }
+    resolve(JSON.parse(str))
   } catch (err) {
+    reject(createError(400, 'Invalid JSON', err))
+  }
+}
+
+exports.json = (req, {limit = '1mb'} = {}) => new Promise((resolve, reject) => {
+  const type = req.headers['content-type']
+  const length = req.headers['content-length']
+  const encoding = typer.parse(type).parameters.charset
+
+  let str = rawBodyMap.get(req)
+
+  if (str) {
+    returnJSON(resolve, reject, str)
+    return
+  }
+
+  getRawBody(req, {limit, length, encoding}).then(buf => {
+    str = buf
+    rawBodyMap.set(req, str)
+
+    returnJSON(resolve, reject, str)
+  }).catch(err => {
     if (err.type === 'entity.too.large') {
       throw createError(413, `Body exceeded ${limit} limit`, err)
     } else {
       throw createError(400, 'Invalid body', err)
     }
-  }
-}
+  })
+})
 
 function send(res, code, obj = null) {
   res.statusCode = code

package.json

@@ -70,6 +70,7 @@
     "isstream": "0.1.2",
     "media-typer": "0.3.0",
     "node-version": "1.0.0",
+    "q": "1.4.1",
     "raw-body": "2.2.0",
     "update-notifier": "1.0.3"
   }

test/index.js

@@ -318,30 +318,22 @@ test('json limit (below)', async t => {
 
 test('json limit (over)', async t => {
   const fn = async (req, res) => {
-    const body = await json(req, {
-      limit: 3
-    })
+    let body
+
+    try {
+      body = await json(req, {
+        limit: 3
+      })
+    } catch (err) {
+      t.deepEqual(err.statusCode, 413)
+    }
 
     send(res, 200, {
       response: body.some.cool
     })
   }
 
-  const url = await getUrl(fn)
-
-  try {
-    await request(url, {
-      method: 'POST',
-      body: {
-        some: {
-          cool: 'json'
-        }
-      },
-      json: true
-    })
-  } catch (err) {
-    t.deepEqual(err.statusCode, 413)
-  }
+  await getUrl(fn)
 })
 
 test('json circular', async t => {
@@ -382,28 +374,20 @@ test('no async', async t => {
 
 test('limit included in error', async t => {
   const fn = async (req, res) => {
-    const body = await json(req, {
-      limit: 3
-    })
+    let body
+
+    try {
+      body = await json(req, {
+        limit: 3
+      })
+    } catch (err) {
+      t.truthy(/exceeded 3 limit/.test(err.message))
+    }
 
     send(res, 200, {
       response: body.some.cool
     })
   }
 
-  const url = await getUrl(fn)
-
-  try {
-    await request(url, {
-      method: 'POST',
-      body: {
-        some: {
-          cool: 'json'
-        }
-      },
-      json: true
-    })
-  } catch (err) {
-    t.truthy(/exceeded 3 limit/.test(err.message))
-  }
+  await getUrl(fn)
 })