Added isEnabled() API method for checking logger enablement (#60)

* Exported `isEnabled()` as API method

* Added documentation for `isEnabled()` API method

readme.md

@@ -749,6 +749,28 @@ signale.success('foo');
 //=> ✔  success  foo
 ```
 
+#### signale.`isEnabled()`
+
+Checks whether the logging functionality of a specific instance is enabled.
+
+```js
+const signale = require('signale');
+
+signale.success('foo');
+//=> ✔  success  foo
+
+signale.isEnabled();
+// => true
+
+signale.disable();
+
+signale.success('foo');
+//=>
+
+signale.isEnabled();
+// => false
+```
+
 ## Development
 
 For more info on how to contribute to the project, please read the [contributing guidelines](https://github.com/klauscfhq/signale/blob/master/contributing.md).

signale.js

@@ -47,10 +47,6 @@ class Signale {
     });
   }
 
-  get isEnabled() {
-    return !this._disabled;
-  }
-
   get date() {
     return new Date().toLocaleDateString();
   }
@@ -256,7 +252,7 @@ class Signale {
   }
 
   _log(message, streams = this._stream) {
-    if (this.isEnabled) {
+    if (this.isEnabled()) {
       this._formatStream(streams).forEach(stream => {
         this._write(stream, message);
       });
@@ -295,6 +291,10 @@ class Signale {
     this._disabled = false;
   }
 
+  isEnabled() {
+    return !this._disabled;
+  }
+
   scope(...name) {
     if (name.length === 0) {
       throw new Error('No scope name was defined.');