Update README and add debug functionality

README.md

@@ -22,7 +22,7 @@ EventSource = SSE;
 var source = new SSE(url, options);
 ```
 
-## Basic usage
+## Usage
 
 The most simple way to use `SSE` is to create the `SSE` object, attach
 one or more listeners, and activate the stream:
@@ -48,6 +48,42 @@ source.addEventListener('message', (e) => { ... });
 source.stream();
 ```
 
+### Passing custom headers
+
+```js
+var source = new SSE(url, {headers: {'Authorization': 'Bearer 0xdeadbeef'}});
+```
+
+### Making a POST request and overriding the HTTP method
+
+To make a HTTP POST request, simply specify a `payload` in the options:
+
+```js
+var source = new SSE(url, {headers: {'Content-Type': 'text/plain'},
+                           payload: 'Hello, world!'});
+```
+
+Alternatively, you can also manually override the HTTP method used to
+perform the request, regardless of the presence of a `payload` option, by
+specifying the `method` option:
+
+```js
+var source = new SSE(url, {headers: {'Content-Type': 'text/plain'},
+                           payload: 'Hello, world!',
+                           method: 'GET'});
+```
+
+### Options reference
+
+| Name              | Description |
+| ----------------- | ----------- |
+| `headers`         | A map of additional headers to use on the HTTP request |
+| `method`          | Override HTTP method (defaults to `GET`, unless a payload is given, in which case it defaults to `POST`) |
+| `payload`         | An optional request payload to sent with the request |
+| `withCredentials` | If set to `true`, CORS requests will be set to include credentials |
+| `start`           | Automatically execute the request and start streaming (defaults to `true`) |
+| `debug`           | Log debug messages to the console about received chunks and dispatched events (defaults to `false`) |
+
 ## Events
 
 `SSE` implements the `EventTarget` interface (just like `EventSource`)
@@ -100,30 +136,6 @@ source.onstatus = function(e) { ... };
 You can mix both `on<event>` and `addEventListener()`. The `on<event>`
 handler is always called first if it is defined.
 
-## Passing custom headers
-
-```js
-var source = new SSE(url, {headers: {'Authorization': 'Bearer 0xdeadbeef'}});
-```
-
-## Making a POST request and overriding the HTTP method
-
-To make a HTTP POST request, simply specify a `payload` in the options:
-
-```js
-var source = new SSE(url, {headers: {'Content-Type': 'text/plain'},
-                           payload: 'Hello, world!'});
-```
-
-Alternatively, you can also manually override the HTTP method used to
-perform the request, regardless of the presence of a `payload` option, by
-specifying the `method` option:
-
-```js
-var source = new SSE(url, {headers: {'Content-Type': 'text/plain'},
-                           payload: 'Hello, world!',
-                           method: 'GET'});
-```
 
 ## Expected response from server
 
@@ -143,16 +155,6 @@ request that the outgoing HTTP request be made with a CORS credentials
 mode of `include`, as per the [HTML Living
 Standard](https://fetch.spec.whatwg.org/#concept-request-credentials-mode).
 
-## Options reference
-
-| Name              | Description |
-| ----------------- | ----------- |
-| `headers`         | A map of additional headers to use on the HTTP request |
-| `method`          | Override HTTP method (defaults to `GET`, unless a payload is given, in which case it defaults to `POST`) |
-| `payload`         | An optional request payload to sent with the request |
-| `withCredentials` | If set to `true`, CORS requests will be set to include credentials |
-| `start`           | Automatically execute the request and start streaming (defaults to `true`) |
-
 ## TODOs and caveats
 
 - Internet Explorer 11 does not support arbitrary values in

lib/sse.js

@@ -20,6 +20,7 @@ var SSE = function (url, options) {
   this.payload = options.payload !== undefined ? options.payload : '';
   this.method = options.method || (this.payload && 'POST' || 'GET');
   this.withCredentials = !!options.withCredentials;
+  this.debug = !!options.debug;
 
   this.FIELD_SEPARATOR = ':';
   this.listeners = {};
@@ -62,6 +63,10 @@ var SSE = function (url, options) {
       return true;
     }
 
+    if (this.debug) {
+      console.debug(e);
+    }
+
     e.source = this;
 
     var onHandler = 'on' + e.type;
@@ -150,6 +155,10 @@ var SSE = function (url, options) {
       return null;
     }
 
+    if (this.debug) {
+      console.debug(chunk);
+    }
+
     var e = {'id': null, 'retry': null, 'data': null, 'event': 'message'};
     chunk.split(/\n|\r\n|\r/).forEach(function(line) {
       line = line.trimRight();