koa-convert - npm Package Compare versions

Comparing version 0.0.2 to 1.0.0

index.js

@@ -1,23 +0,33 @@
-'use strict';
+'use strict'
 
 const co = require('co')
+const compose = require('koa-compose')
 
 module.exports = convert
 
-function convert(mw) {
-    if (typeof mw !== 'function') {
-        throw new TypeError(mw + ' is not function')
+function convert (mw) {
+  if (typeof mw !== 'function') {
+    throw new TypeError('middleware must be a function')
+  }
+  if (mw.constructor.name === 'GeneratorFunction') {
+    return function (ctx, next) {
+      return co.call(ctx, mw.call(ctx, createGenerator(next)))
     }
-    if (mw.constructor.name === 'GeneratorFunction') {
-        return function (ctx, next) {
-            return co.call(ctx, mw.call(ctx, createGenerator(next)))
-        }
-    } else {
-        // assume it's Promise-based middleware
-        return mw
-    }
+  } else {
+    // assume it's Promise-based middleware
+    return mw
+  }
 }
 
-function* createGenerator(next) {
-    return yield next()
+// 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))
 }
+
+function * createGenerator (next) {
+  return yield next()
+}

package.json

 {
   "name": "koa-convert",
-  "version": "0.0.2",
+  "version": "1.0.0",
   "keywords": [
@@ -9,7 +9,3 @@ "koa",
   ],
-  "description": "convert koa generator-based middleware to promise-based middleware",
-  "main": "index.js",
-  "scripts": {
-    "test": "mocha test.js"
-  },
+  "description": "convert koa legacy generator-based middleware to promise-based middleware",
   "repository": {
@@ -19,2 +15,6 @@ "type": "git",
   },
+  "main": "index.js",
+  "scripts": {
+    "test": "standard && mocha test.js"
+  },
   "author": "gyson <[e-mail]>",
@@ -27,7 +27,14 @@ "license": "MIT",
   "dependencies": {
-    "co": "^4.6.0"
+    "co": "^4.6.0",
+    "koa-compose": "^3.0.0"
   },
   "devDependencies": {
-    "mocha": "^2.3.3"
+    "koa": "^2.0.0-alpha.2",
+    "mocha": "^2.3.3",
+    "standard": "^5.3.1",
+    "supertest": "^1.1.0"
+  },
+  "engines": {
+    "node": ">= 4"
   }
 }

README.md

 
 # koa-convert
 
-Convert koa generator-based middleware to promise-based middleware.
+[![npm version](https://img.shields.io/npm/v/koa-convert.svg)](https://npmjs.org/package/koa-convert)
+[![build status](https://travis-ci.org/gyson/koa-convert.svg)](https://travis-ci.org/gyson/koa-convert)
 
+Convert koa legacy ( 0.x & 1.x ) generator middleware to modern promise middleware ( 2.x ).
+
 ## Installation
@@ -12,46 +15,105 @@
 
-## Related Issues
+## Usage
 
-* koa [#415](https://github.com/koajs/koa/issues/415)
-* koa-compose [#27](https://github.com/koajs/compose/pull/27)
+```js
+const Koa = require('koa') // koa v2.x
+const convert = require('koa-convert')
+const app = new Koa()
 
-## Usage
+app.use(modernMiddleware)
 
+app.use(convert(legacyMiddleware))
+
+app.use(convert.compose(legacyMiddleware, modernMiddleware))
+
+function * legacyMiddleware (next) {
+  // before
+  yield next
+  // after
+}
+
+function modernMiddleware (ctx, next) {
+  // before
+  return next().then(() => {
+    // after
+  })
+}
+```
+
+## 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).
+
+Therefore, we can distinguish legacy and modern middleware with `fn.constructor.name == 'GeneratorFunction'`.
+
+## Migration
+
+`app.use(legacyMiddleware)` is everywhere in 0.x and 1.x and it would be painful to manually change all of them to `app.use(convert(legacyMiddleware))`.
+
+You can use following snippet to make migration easier.
+
 ```js
+const _use = app.use
+app.use = x => _use.call(app, convert(x))
+```
+
+The above snippet will override `app.use` method and implicitly convert all legacy generator middleware to modern promise middleware.
+
+Therefore, you can have both `app.use(modernMiddleware)` and `app.use(legacyMiddleware)` and your 0.x or 1.x should work without modification.
+
+Complete example:
+
+```js
+const Koa = require('koa') // v2.x
 const convert = require('koa-convert')
+const app = new Koa()
 
-//
-// convert a generator-based middleware to promise-based middleware
-//
-let promiseBased = convert(function* generatorBased(next) {
-    yield next
-    // or
-    // yield* next
-})
+// ---------- override app.use method ----------
 
-//
-// convert array of middleware
-//
-let mws = [
-    // will convert it to promise-based middleware
-    function* generatorMW (next) {
-        yield next
-    },
-    // will convert it to promise-based middleware
-    function* generatorMW(next) {
-        yield* next
-    },
-    // return itself if it's not generator-based middleware
-    function (ctx, next) {
-        return next()
-    },
-    // return itself if it's not generator-based middleware
-    async function (ctx, next) {
-        await next()
-    },
-].map(convert)
+const _use = app.use
+app.use = x => _use.call(app, convert(x))
+
+// ---------- end ----------
+
+app.use(modernMiddleware)
+
+// this will be converted to modern promise middleware implicitly
+app.use(legacyMiddleware)
+
+function * legacyMiddleware (next) {
+  // before
+  yield next
+  // after
+}
+
+function modernMiddleware (ctx, next) {
+  // before
+  return next().then(() => {
+    // after
+  })
+}
 ```
 
+## API
+
+#### `convert()`
+
+Convert legacy generator middleware to modern promise middleware
+
+```js
+app.use(convert(legacyMiddleware))
+```
+
+#### `convert.compose()`
+
+Convert and compose multiple middleware (could mix legacy and modern ones) and return modern promise middleware
+
+```js
+app.use(convert.compose(legacyMiddleware, modernMiddleware))
+// or
+app.use(convert.compose([legacyMiddleware, modernMiddleware]))
+```
+
 ## License
 
 MIT

test.js

@@ -1,61 +0,189 @@
-'use strict';
+/* global describe, it */
 
+'use strict'
+
 const co = require('co')
+const Koa = require('koa')
 const assert = require('assert')
 const convert = require('./index')
+const request = require('supertest')
 
-describe('Koa Convert', function () {
-    it('should works', function (done) {
-        let call = []
-        let ctx = {}
-        let mw = convert(function* (next) {
-            assert.ok(ctx === this)
-            call.push(1)
-        })
+describe('convert()', () => {
+  it('should work', () => {
+    let call = []
+    let ctx = {}
+    let mw = convert(function * (next) {
+      assert.ok(ctx === this)
+      call.push(1)
+    })
 
-        mw(ctx, function () {
-            done(new Error('this should not be called'))
-        }).then(function () {
-            assert.deepEqual(call, [1])
-            done()
-        })
+    return mw(ctx, function () {
+      call.push(2)
+    }).then(function () {
+      assert.deepEqual(call, [1])
     })
+  })
 
-    it('should works with `yield next`', function (done) {
-        let call = []
-        let ctx = {}
-        let mw = convert(function* (next) {
-            assert.ok(ctx === this)
-            call.push(1)
-            yield next
-            call.push(3)
+  it('should work with `yield next`', () => {
+    let call = []
+    let ctx = {}
+    let mw = convert(function * (next) {
+      assert.ok(ctx === this)
+      call.push(1)
+      yield next
+      call.push(3)
+    })
+
+    return mw(ctx, function () {
+      call.push(2)
+      return Promise.resolve()
+    }).then(function () {
+      assert.deepEqual(call, [1, 2, 3])
+    })
+  })
+
+  it('should work with `yield* next`', () => {
+    let call = []
+    let ctx = {}
+    let mw = convert(function * (next) {
+      assert.ok(ctx === this)
+      call.push(1)
+      yield* next
+      call.push(3)
+    })
+
+    return mw(ctx, function () {
+      call.push(2)
+      return Promise.resolve()
+    }).then(function () {
+      assert.deepEqual(call, [1, 2, 3])
+    })
+  })
+})
+
+describe('convert.compose()', () => {
+  it('should work', () => {
+    let call = []
+    let context = {}
+    let _context
+    let mw = convert.compose([
+      function * name (next) {
+        call.push(1)
+        yield next
+        call.push(11)
+      },
+      (ctx, next) => {
+        call.push(2)
+        return next().then(() => {
+          call.push(10)
         })
+      },
+      function * (next) {
+        call.push(3)
+        yield* next
+        call.push(9)
+      },
+      co.wrap(function * (ctx, next) {
+        call.push(4)
+        yield next()
+        call.push(8)
+      }),
+      function * (next) {
+        try {
+          call.push(5)
+          yield next
+        } catch (e) {
+          call.push(7)
+        }
+      },
+      (ctx, next) => {
+        _context = ctx
+        call.push(6)
+        throw new Error()
+      }
+    ])
 
-        mw(ctx, function () {
-            call.push(2)
-            return Promise.resolve()
-        }).then(function () {
-            assert.deepEqual(call, [1, 2, 3])
-            done()
-        })
+    return mw(context).then(() => {
+      assert.equal(context, _context)
+      assert.deepEqual(call, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11])
     })
+  })
 
-    it('should works with `yield* next`', function (done) {
-        let call = []
-        let ctx = {}
-        let mw = convert(function* (next) {
-            assert.ok(ctx === this)
-            call.push(1)
-            yield* next
-            call.push(3)
+  it('should work too', () => {
+    let call = []
+    let context = {}
+    let _context
+    let mw = convert.compose(
+      (ctx, next) => {
+        call.push(1)
+        return next().catch(() => {
+          call.push(4)
         })
+      },
+      function * (next) {
+        call.push(2)
+        yield next
+        call.push(-1) // should not call this
+      },
+      function * (next) {
+        call.push(3)
+        yield* next
+        call.push(-1) // should not call this
+      },
+      (ctx, next) => {
+        _context = ctx
+        return Promise.reject(new Error())
+      }
+    )
 
-        mw(ctx, function () {
-            call.push(2)
-            return Promise.resolve()
-        }).then(function () {
-            assert.deepEqual(call, [1, 2, 3])
-            done()
-        })
+    return mw(context).then(() => {
+      assert.equal(context, _context)
+      assert.deepEqual(call, [1, 2, 3, 4])
     })
+  })
 })
+
+describe('migration snippet', () => {
+  let app = new Koa()
+
+  // snippet
+  const _use = app.use
+  app.use = x => _use.call(app, convert(x))
+  // end
+
+  app.use((ctx, next) => {
+    ctx.body = [1]
+    return next().then(() => {
+      ctx.body.push(9)
+    })
+  })
+
+  app.use(function * (next) {
+    this.body.push(2)
+    yield next
+    this.body.push(8)
+  })
+
+  app.use(function * (next) {
+    this.body.push(3)
+    yield* next
+    this.body.push(7)
+  })
+
+  app.use(co.wrap(function * (ctx, next) {
+    ctx.body.push(4)
+    yield next()
+    ctx.body.push(6)
+  }))
+
+  app.use(ctx => {
+    ctx.body.push(5)
+  })
+
+  it('should work', done => {
+    request(app.callback())
+      .get('/')
+      .expect(200, [1, 2, 3, 4, 5, 6, 7, 8, 9])
+      .end(done)
+  })
+})

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Improved metrics

Total package byte prevSize

9291

increased by93.12%

Number of package files

7

increased by16.67%

Lines of code

197

increased by169.86%

Number of low quality alerts

0

decreased by-100%

Number of lines in readme file

119

increased by108.77%

Worsened metrics

Dependency count

2

increased by100%

Dev dependency count

4

increased by300%

Dependency changes

• + Addedkoa-compose@^3.0.0

• + Addedany-promise@1.3.0(transitive)

• + Addedkoa-compose@3.2.1(transitive)