keeping track of ranges in an array

src/routes/merge/+page.svelte

@@ -35,6 +35,26 @@
 		interv = setInterval(animate, 1000 / FPS);
 	});
 
+	class ArrRef {
+		/**
+		 * @param {number} start
+		 * @param {number} end
+		 */
+		constructor(start, end) {
+			this.start = start;
+			this.end = end;
+			this.length = end - start;
+		}
+
+		/**
+		 * @param {number} index
+		 * @returns {number}
+		 */
+		at(index) {
+			return data[this.start + index];
+		}
+	}
+
 	/** Render a single frame of the sorting algorithm at a time on the canvas. */
 	function animate() {
 		// Clear canvas with black background