koa-compose - npm Package Compare versions

Comparing version 2.0.1 to 2.1.0

index.js

 
 /**
+ * Module dependencies.
+ */
+
+var debug = require('debug')('koa-compose');
+var fmt = require('util').inspect;
+
+/**
  * Expose compositor.
  */
 
-module.exports = compose;
+module.exports = debug.enabled
+  ? instrumented
+  : compose;
 
@@ -19,20 +28,46 @@ /**
 function compose(middleware){
-  return function *(downstream){
-    var done = false;
-    var ctx = this;
-    var i = 0;
+  return function *(next){
+    var i = middleware.length;
+    var prev = next || noop();
+    var curr;
 
-    yield *next();
+    while (i--) {
+      curr = middleware[i];
+      prev = curr.call(this, prev);
+    }
 
-    function next(){
-      var mw = middleware[i++];
+    yield *prev;
+  }
+}
 
-      if (!mw) {
-        if (done) throw new Error('middleware yielded control multiple times');
-        done = true;
-        return downstream || noop();
-      }
+/**
+ * Compose `middleware` returning
+ * an instrumented set of middleware
+ * for debugging manipulation between
+ * continuation.
+ *
+ * @param {Array} middleware
+ * @return {Function}
+ * @api public
+ */
 
-      return mw.call(ctx, next());
+function instrumented(middleware){
+  console.warn('Warning: do not run DEBUG=koa-compose in production');
+  console.warn('as it will greatly affect the performance of your');
+  console.warn('application - it is designed for a development');
+  console.warn('environment only.\n');
+
+  return function *(next){
+    var i = middleware.length;
+    var prev = next || noop();
+    var name = prev.name || 'noop';
+    var curr;
+
+    while (i--) {
+      curr = middleware[i];
+      prev = wrap.call(this, curr, prev, name);
+      name = curr.name;
     }
+
+    yield *prev;
   }
@@ -42,2 +77,32 @@ }
 /**
+ * Wrap to output debugging info.
+ *
+ * @api private
+ */
+
+function wrap(curr, prev, name) {
+  return curr.call(this, function *(next){
+    if ('noop' == name) return yield next;
+    this._level = this._level || 0;
+
+    // downstream
+    console.log('  \033[1m%d | \033[0m>> \033[36m%s\033[0m', this._level, name);
+    console.log();
+    console.log(fmt(this.response, { depth: 5, colors: true }).replace(/^/gm, '  '));
+    console.log();
+
+    // yield
+    this._level++;
+    yield next;
+    this._level--;
+
+    // upstream
+    console.log('  \033[1m%d | \033[0m<< \033[36m%s\033[0m', this._level, name);
+    console.log();
+    console.log(fmt(this.response, { depth: 5, colors: true }).replace(/^/gm, '  '));
+    console.log();
+  }.call(this, prev));
+}
+
+/**
  * Noop.
@@ -44,0 +109,0 @@ *

package.json

@@ -5,10 +5,19 @@ {
   "repository": "koajs/compose",
-  "version": "2.0.1",
-  "keywords": ["koa", "middleware", "compose"],
-  "files": ["index.js"],
-  "dependencies": { "debug": "*" },
+  "version": "2.1.0",
+  "keywords": [
+    "koa",
+    "middleware",
+    "compose"
+  ],
+  "files": [
+    "index.js"
+  ],
+  "dependencies": {
+    "debug": "*"
+  },
   "devDependencies": {
     "co": "~3.0.1",
     "mocha": "~1.6.0",
-    "should": "~2.1.0"
+    "should": "~2.1.0",
+    "koa": "~0.1.2"
   },
@@ -19,2 +28,2 @@ "scripts": {
   "license": "MIT"
-}
+}

Readme.md

@@ -12,4 +12,18 @@
 
+## Debugging
+
+  To debug the interactions between middleware, you may use
+  the __DEBUG__ environment variable, for example:
+
+```
+$ DEBUG=koa-compose node --harmony app.js
+```
+
+  When enabled this will output verbose response information and the
+  middleware names to help visualize how they interact.
+
+  ![koa middleware debugging](https://dl.dropboxusercontent.com/u/6396913/koa/Screen%20Shot%202013-12-22%20at%208.46.46%20AM.png)
+
 ## License
 
   MIT

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Improved metrics

Total package byte prevSize

3347

increased by149.78%

Lines of code

90

increased by157.14%

Number of lines in readme file

28

increased by100%

Number of medium supply chain risk alerts

0

decreased by-100%

Worsened metrics

Dev dependency count

4

increased by33.33%

No dependency changes