Merge pull request #23 from bitvavo/chore/add_unsubscribe

Fix on: [chore: add unsubscribe websocket method #18](#18)

### Add
- `unsubscribe` Websocket action

Author: ca42rico

README.md

@@ -45,6 +45,7 @@ To trade and execute your advanced trading strategies, Bitvavo SDK for Node.js i
   * [Trades Subscription](#trades-subscription)
   * [Book Subscription](#book-subscription)
   * [Book Subscription With Local Copy](#book-subscription-with-local-copy)
+  * [Unsubscribe](#unsubscribe)
 
 ## Installation
 ```
@@ -2822,3 +2823,14 @@ bitvavo.websocket.subscriptionBook('LTC-EUR', (book) => {
   nonce: 41175 }
 ```
 </details>
+
+#### Unsubscribe
+Unsubscribe from a previously opened websocket connection.
+```javascript
+bitvavo.websocket.unsubscribe('LTC-EUR', 'account')
+```
+<details>
+ <summary>View Response</summary>
+```javascript
+{ event: 'unsubscribed', subscriptions: {} }
+```

node-bitvavo-api.js

@@ -919,6 +919,12 @@ let api = function Bitvavo () {
         await this.checkSocket()
         doSendPublic(this.websocket, JSON.stringify({ 'action': 'getBook', 'market': market }))
         doSendPublic(this.websocket, JSON.stringify({ 'action': 'subscribe', 'channels': [{ 'name': 'book', 'markets': [market] }] }))
+      },
+
+      unsubscribe: async function (market = '', name = undefined) {
+        if (typeof name === 'undefined') errorToConsole('Specify which channel you want to unsubscribe from (such as: ticker, ticker24h, candles, trades, account and book.)');
+        await this.checkSocket();
+        doSendPrivate(this.websocket, JSON.stringify({ 'action': 'unsubscribe', 'channels': [{ 'name': name, 'markets': [market] }] }));
       }
     }
   }

package.json

@@ -1,6 +1,6 @@
 {
     "name": "bitvavo",
-    "version": "1.2.2",
+    "version": "1.2.3",
     "description": "This is the NodeJS wrapper for the Bitvavo API",
     "main": "node-bitvavo-api.js",
     "directories": {
@@ -25,5 +25,4 @@
       "url": "https://github.com/bitvavo/node-bitvavo-api/issues"
     },
     "homepage": "https://github.com/bitvavo/node-bitvavo-api#readme"
-  }
-  
+}