Add ctx.wrappers array

docs/api/context.md

@@ -58,6 +58,15 @@ app.use(async (ctx, next) => {
 ctx.state.user = await User.find(id);
 ```
 
+### ctx.wrappers
+
+  Stores functions to wrap middleware (e.g. co.wrap could be used).
+  Note that koa itself does not implement the use of these wrappers, they are implemented by utilities such as koa-compose.
+
+```js
+ctx.wrappers.push(co.wrap);
+```
+
 ### ctx.app
 
   Application instance reference.

lib/application.js

@@ -164,6 +164,7 @@ module.exports = class Application extends Emitter {
     request.ip = request.ips[0] || req.socket.remoteAddress || '';
     context.accept = request.accept = accepts(req);
     context.state = {};
+    context.wrappers = [];
     return context;
   }
 

test/context/wrappers.js

@@ -0,0 +1,23 @@
+
+'use strict';
+
+const request = require('supertest');
+const assert = require('assert');
+const Koa = require('../..');
+
+describe('ctx.wrappers', () => {
+  it('should provide a ctx.wrappers array', done => {
+    const app = new Koa();
+
+    app.use(ctx => {
+      assert(ctx.wrappers instanceof Array);
+    });
+
+    const server = app.listen();
+
+    request(server)
+      .get('/')
+      .expect(404)
+      .end(done);
+  });
+});