add variadic arg support (#65)

* add variadic arg support

ref #63

* remove array check

* fix varargs test

index.js

@@ -1,6 +1,7 @@
 'use strict'
 
 const Promise = require('any-promise')
+const flatten = require('lodash/flatten')
 
 /**
  * Expose compositor.
@@ -13,13 +14,13 @@ module.exports = compose
  * a fully valid middleware comprised
  * of all those which are passed.
  *
- * @param {Array} middleware
+ * @param {Array|Function...} middleware
  * @return {Function}
  * @api public
  */
 
 function compose (middleware) {
-  if (!Array.isArray(middleware)) throw new TypeError('Middleware stack must be an array!')
+  middleware = flatten(arguments)
   for (const fn of middleware) {
     if (typeof fn !== 'function') throw new TypeError('Middleware must be composed of functions!')
   }

package.json

@@ -12,7 +12,8 @@
     "index.js"
   ],
   "dependencies": {
-    "any-promise": "^1.1.0"
+    "any-promise": "^1.1.0",
+    "lodash": "^4.16.4"
   },
   "devDependencies": {
     "co": "^4.6.0",

test/test.js

@@ -85,14 +85,16 @@ describe('Koa Compose', function () {
     })
   })
 
-  it('should only accept an array', function () {
-    var err
-    try {
-      (compose()).should.throw()
-    } catch (e) {
-      err = e
-    }
-    return (err).should.be.instanceof(TypeError)
+  it('should support variadic arguments', function () {
+    const arr = []
+    const gen = str => (ctx, next) => new Promise((resolve, reject) => {
+      arr.push(str)
+      next()
+      resolve()
+    })
+
+    const promise = compose(gen('a'), gen('b'), gen('c'))({})
+    return promise.then(() => arr.should.eql([ 'a', 'b', 'c' ]))
   })
 
   it('should work with 0 middleware', function () {