added sprite files

js/Sprites.js

@@ -0,0 +1,28 @@
+export default class SpriteSheet {
+  constructor(image, width, height) {
+    this.image = image
+    this.width = width
+    this.height = height
+    this.tiles = new Map()
+  }
+  define(name, x, y) {
+    const buffer = document.creatElement('canvas')
+    buffer.width = this.width
+    buffer.height = this.height
+    buffer.getContext('2d')
+    buffer.drawImage( this.image,
+                      x * this.width,
+                      y * thix.height,
+                      this.width,
+                      this.height,
+                      0,
+                      0,
+                      this.width,
+                      this.height)
+    this.tiles.set(name, buffer)
+  }
+  draw(name, context, x, y) {
+    const buffer = this.tiles.get(name)
+    context.drawImage(buffer, x, y)
+  }
+}