allow serializer methods to return a promise

lib/dispatch/end.js

@@ -49,8 +49,6 @@ export default function (context) {
     if (records) args.push(records)
     if (include) args.push(include)
 
-    context = serializer.showResponse(...args)
-
-    return context
+    return serializer.showResponse(...args)
   })
 }

lib/dispatch/index.js

@@ -64,15 +64,15 @@ export default function dispatch (options, ...args) {
     return new OK(response)
   })
 
-  .catch(error => {
-    context = showError(context, nativeErrors.has(error.constructor) ?
-      new Error(`An internal server error occurred.`) : error)
+  .catch(error => Promise.resolve(
+    showError(context, nativeErrors.has(error.constructor) ?
+      new Error(`An internal server error occurred.`) : error))
+
+    .then(context => Promise.resolve(processResponse(context, ...args)))
 
-    return Promise.resolve(processResponse(context, ...args))
     .then(context => {
       throw Object.assign(error, context.response)
-    })
-  })
+    }))
 }
 
 

lib/serializer/index.js

@@ -87,7 +87,7 @@ export default class Serializer {
    * @param {Object} context
    * @param {Object[]} [records]
    * @param {Object} [include]
-   * @return {Object}
+   * @return {Promise|Object}
    */
   showResponse (context) {
     return context
@@ -100,7 +100,7 @@ export default class Serializer {
    *
    * @param {Object} context
    * @param {Object} error should be an instance of Error
-   * @return {Object}
+   * @return {Promise|Object}
    */
   showError (context) {
     return context

lib/serializer/singleton.js

@@ -81,10 +81,6 @@ export default class SerializerSingleton extends Serializer {
 
 
 const inputMethods = new Set([ 'parseCreate', 'parseUpdate' ])
-const asynchronousMethods = new Set([
-  'processRequest', 'processResponse',
-  'parseCreate', 'parseUpdate'
-])
 
 
 // Assign the proxy methods on top of the base methods.
@@ -124,19 +120,17 @@ function proxyMethod (options, context, ...args) {
   // Fail if no serializer was found.
   else throw new NoopError(`The serializer for "${format}" is unrecognized.`)
 
-  const isAsynchronous = asynchronousMethods.has(method)
-
   try {
-    const result = serializer[method](context, ...args)
-    return isAsynchronous ? Promise.resolve(result) : result
+    return Promise.resolve(serializer[method](context, ...args))
   }
   catch (e) {
     let error = e
 
+    // Only in the special case of input methods, it may be more appropriate to
+    // throw a BadRequestError.
     if (nativeErrors.has(error.constructor) && isInput)
       error = new BadRequestError(`The request is malformed.`)
 
-    if (isAsynchronous) return Promise.reject(error)
-    throw error
+    return Promise.reject(error)
   }
 }