Remove Source._type

src/sources/canvas-source.ts

     }
 
     /**
-     * A type-identifier of the source of data
-     * @internal
-     */
-    get _type(): keyof SourceType
-    {
-        return 'canvas';
-    }
-
-    /**
      * Check if this source is of a certain type
      * @internal
      */
     _is<T extends keyof SourceType>(type: T): this is SourceType[T]
     {
-        return type === this._type;
+        return type === 'canvas';
     }
 
     /**
     _init(): SpeedyPromise<void>
     {
         return Speedy.load(this._canvas).then(media => {
-            Utils.log(`Source of data is a ${media.width}x${media.height} ${this._type}`);
+            Utils.log(`Source of data is a ${media.width}x${media.height} canvas`);
             this._media = media;
         });
     }

src/sources/pointer-source.ts

     }
 
     /**
-     * A type-identifier of the source of data
-     * @internal
-     */
-    get _type(): keyof SourceType
-    {
-        return 'pointer-source';
-    }
-
-    /**
      * Check if this source is of a certain type
      * @internal
      */
     _is<T extends keyof SourceType>(type: T): this is SourceType[T]
     {
-        return type === this._type;
+        return type === 'pointer-source';
     }
 
     /**

src/sources/source.ts

  */
 export interface Source
 {
-    /** @internal type-identifier of the source of data */
-    readonly _type: keyof SourceType;
-
     /** @internal check if this source is of a certain type */
     _is<T extends keyof SourceType>(type: T): this is SourceType[T];
 

src/sources/video-source.ts

     }
 
     /**
-     * A type-identifier of the source of data
-     * @internal
-     */
-    get _type(): keyof SourceType
-    {
-        return 'video';
-    }
-
-    /**
      * Check if this source is of a certain type
      * @internal
      */
     _is<T extends keyof SourceType>(type: T): this is SourceType[T]
     {
-        return type === this._type;
+        return type === 'video';
     }
 
     /**
      */
     _init(): SpeedyPromise<void>
     {
-        Utils.log(`Initializing ${this._type} source...`);
+        Utils.log(`Initializing video source...`);
 
         // prepare the video before loading the SpeedyMedia!
         return this._prepareVideo(this._video).then(video => {
             Utils.log('The video is prepared');
 
             return Speedy.load(video).then(media => {
-                Utils.log(`Source of data is a ${media.width}x${media.height} ${this._type}`);
+                Utils.log(`Source of data is a ${media.width}x${media.height} video`);
                 this._media = media;
             });
         });