update: ready to next release

.gitignore

@@ -1 +1,20 @@
+
+#       OS        #
+###################
+.DS_Store
+.idea
+Thumbs.db
+tmp
+temp
+
+
+#     Node.js     #
+###################
 node_modules
+package-lock.json
+
+
+#       NYC       #
+###################
+coverage
+.nyc_output

.nycrc

@@ -0,0 +1,15 @@
+{
+  "extension": [
+    ".js"
+  ],
+  "exclude": [
+    "index.spec.js"
+  ],
+  "reporter": [
+    "text-lcov",
+    "text",
+    "lcov"
+  ],
+  "report-dir": "./coverage",
+  "temp-dir": "./.nyc_output"
+}

.travis.yml

@@ -1,5 +1,7 @@
 language: node_js
 node_js:
-  - "4"
-  - "5"
-script: "npm run test"
+  - 10
+  - 12
+  - 14
+script: 
+  - npm run ci

LICENSE

@@ -1,6 +1,7 @@
 The MIT License (MIT)
 
 Copyright (c) 2015 yunsong
+Copyright (c) 2020 Koa.js contributors
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -19,4 +20,3 @@ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
-

README.md

@@ -1,12 +1,34 @@
-
 # koa-convert
 
-[![npm version](https://img.shields.io/npm/v/koa-convert.svg)](https://npmjs.org/package/koa-convert)
-[![build status](https://travis-ci.org/koajs/convert.svg)](https://travis-ci.org/koajs/convert)
+[![Build Status][travis-img]][travis-url]
+[![NPM version][npm-badge]][npm-url]
+[![License][license-badge]][license-url]
+![Code Size][code-size-badge]
+
+<!-- [![Coverage Status][coverage-img]][coverage-url] -->
+
+<!-- ***************** -->
+
+[travis-img]: https://travis-ci.org/koajs/convert.svg?branch=master
+[travis-url]: https://travis-ci.org/koajs/convert
 
-Convert koa legacy ( 0.x & 1.x ) generator middleware to modern promise middleware ( 2.x ).
+<!-- 
+  WAIT FOR ACCESS 
+  [coverage-img]: https://coveralls.io/repos/github/koajs/convert/badge.svg?branch=master
+  [coverage-url]: https://coveralls.io/github/koajs/convert?branch=master
+-->
 
-It could also convert modern promise middleware back to legacy generator middleware ( useful to help modern middleware support koa 0.x or 1.x ).
+[npm-badge]: https://img.shields.io/npm/v/koa-better-request-id.svg?style=flat
+[npm-url]: https://www.npmjs.com/package/koa-better-request-id
+[license-badge]: https://img.shields.io/badge/license-MIT-green.svg?style=flat-square
+[license-url]: https://github.com/koajs/koa-convert/blob/master/LICENSE
+[code-size-badge]: https://img.shields.io/github/languages/code-size/koajs/koa-convert
+
+<!-- ***************** -->
+
+Convert Koa legacy (0.x & 1.x) generator middleware to modern promise middleware (2.x).
+
+It could also convert modern promise middleware back to legacy generator middleware (useful to help modern middleware support Koa v0.x or v1.x).
 
 ## Note
 
@@ -21,8 +43,11 @@ You may use following packages for [routing](https://github.com/koajs/koa/wiki#r
 
 ## Installation
 
-```
-$ npm install koa-convert
+```bash
+# npm ..
+$ npm i koa-convert
+# yarn ..
+$ yarn add koa-convert
 ```
 
 ## Usage
@@ -54,7 +79,7 @@ function modernMiddleware (ctx, next) {
 
 ## Distinguish legacy and modern middleware
 
-In koa 0.x and 1.x ( without experimental flag ), `app.use` has an assertion that all ( legacy ) middleware must be generator function and it's tested with `fn.constructor.name == 'GeneratorFunction'` at [here](https://github.com/koajs/koa/blob/7fe29d92f1e826d9ce36029e1b9263b94cba8a7c/lib/application.js#L105).
+In koa 0.x and 1.x (without experimental flag), `app.use` has an assertion that all (legacy) middleware must be generator function and it's tested with `fn.constructor.name == 'GeneratorFunction'` at [here](https://github.com/koajs/koa/blob/7fe29d92f1e826d9ce36029e1b9263b94cba8a7c/lib/application.js#L105).
 
 Therefore, we can distinguish legacy and modern middleware with `fn.constructor.name == 'GeneratorFunction'`.
 
@@ -138,4 +163,4 @@ legacyMiddleware = convert.back(modernMiddleware)
 
 ## License
 
-MIT
+[MIT](LICENSE)

index.js

@@ -1,60 +1,105 @@
 'use strict'
 
+/**
+ * Module dependencies.
+ */
+
 const co = require('co')
 const compose = require('koa-compose')
 
+/**
+ * Expose `convert()`.
+ */
+
 module.exports = convert
 
+/**
+ * Convert Koa legacy generator-based middleware
+ * to modern promise-based middleware.
+ *
+ *
+ * @api public
+ * */
+
 function convert (mw) {
   if (typeof mw !== 'function') {
     throw new TypeError('middleware must be a function')
   }
-  if (mw.constructor.name !== 'GeneratorFunction') {
-    // assume it's Promise-based middleware
+
+  // assume it's Promise-based middleware
+  if (
+    mw.constructor.name !== 'GeneratorFunction' &&
+    mw.constructor.name !== 'AsyncGeneratorFunction'
+  ) {
     return mw
   }
+
   const converted = function (ctx, next) {
-    return co.call(ctx, mw.call(ctx, createGenerator(next)))
+    return co.call(
+      ctx,
+      mw.call(
+        ctx,
+        (function * (next) { return yield next() })(next)
+      ))
   }
+
   converted._name = mw._name || mw.name
   return converted
 }
 
-function * createGenerator (next) {
-  return yield next()
-}
+/**
+ * Convert and compose multiple middleware
+ * (could mix legacy and modern ones)
+ * and return modern promise middleware.
+ *
+ *
+ * @api public
+ * */
 
 // convert.compose(mw, mw, mw)
 // convert.compose([mw, mw, mw])
 convert.compose = function (arr) {
   if (!Array.isArray(arr)) {
     arr = Array.from(arguments)
   }
+
   return compose(arr.map(convert))
 }
 
+/**
+ * Convert Koa modern promise-based middleware
+ * to legacy generator-based middleware.
+ *
+ *
+ * @api public
+ * */
+
 convert.back = function (mw) {
   if (typeof mw !== 'function') {
     throw new TypeError('middleware must be a function')
   }
-  if (mw.constructor.name === 'GeneratorFunction') {
-    // assume it's generator middleware
+
+  // assume it's generator middleware
+  if (mw.constructor.name === 'GeneratorFunction' || mw.constructor.name === 'AsyncGeneratorFunction') {
     return mw
   }
+
   const converted = function * (next) {
-    let ctx = this
+    const ctx = this
     let called = false
-    // no need try...catch here, it's ok even `mw()` throw exception
-    yield Promise.resolve(mw(ctx, function () {
+
+    yield mw(ctx, function () {
       if (called) {
         // guard against multiple next() calls
         // https://github.com/koajs/compose/blob/4e3e96baf58b817d71bd44a8c0d78bb42623aa95/index.js#L36
-        return Promise.reject(new Error('next() called multiple times'))
+        throw new Error('next() called multiple times')
       }
+
       called = true
       return co.call(ctx, next)
-    }))
+    })
   }
+
   converted._name = mw._name || mw.name
   return converted
 }