Cleans up settings creation.

main.js

@@ -27,69 +27,55 @@ const btnRedraw_onClick = () => {
 }
 
 const getSettingsForDirection = (direction) => {    
-    const advanceForward = i => i - 1;
-    const advanceBackward = i => i + 1;
-    const testForDoneForward = fromIndex => fromIndex < 0;
-    const testForDoneBackward = (fromIndex, length) => fromIndex >= length;
-    const getInitialFromIndexForward = (length) => length - 2;
-    const getInitialFromIndexBackward = () => 1;
-    const getInitialToIndexForward = (length) => length - 1;
-    const getInitialToIndexBackward = () => 0;
-    const getColumn = (grid, index) =>  grid.getColumn(index);
-    const getRow = (grid, index) => grid.getRow(index);
-    const getNumRows = (grid) => grid.numRows;
-    const getNumColumns = (grid) => grid.numColumns;
-    const swapInRow = (grid, vector, rowIndex, from, to) => {
-        grid.swapTiles(rowIndex, from, rowIndex, to);
-        const tempTile = vector[to];
-        vector[to] = vector[from];
-        vector[from] = tempTile;
-    };
-    const swapInColumn = (grid, vector, columnIndex, from, to) => {
-        grid.swapTiles(from, columnIndex, to, columnIndex);
-        const tempTile = vector[to];
-        vector[to] = vector[from];
-        vector[from] = tempTile;        
-    }
-    const merge = (from, to) => {
+    let settings = { 
+        merge: (from, to) => {
             to.value++;
             from.value = 0;
             from.visible = false;
+        }
     };
 
-    let settings = { merge };
-
     if (direction === Direction.Up || direction === Direction.Left) {
         settings = {
             ...settings,
-            advance: advanceBackward,
-            testForDone: testForDoneBackward,
-            getInitialFromIndex: getInitialFromIndexBackward,
-            getInitialToIndex: getInitialToIndexBackward
+            advance: i => i + 1,
+            testForDone: (fromIndex, length) => fromIndex >= length,
+            getInitialFromIndex: () => 1,
+            getInitialToIndex: () => 0
         };
     } else if (direction === Direction.Down || direction === Direction.Right) {
         settings = {
             ...settings,
-            advance: advanceForward,
-            testForDone: testForDoneForward,
-            getInitialFromIndex: getInitialFromIndexForward,
-            getInitialToIndex: getInitialToIndexForward
+            advance: i => i - 1,
+            testForDone: fromIndex => fromIndex < 0,
+            getInitialFromIndex: (length) => length - 2,
+            getInitialToIndex: (length) => length - 1
         };
     }
 
     if (direction === Direction.Up || direction === Direction.Down) {
         settings = {
             ...settings,
-            getVector: getColumn,
-            swap: swapInColumn,
-            getLength: getNumColumns
+            getVector: (grid, index) =>  grid.getColumn(index),
+            swap: (grid, vector, columnIndex, from, to) => {
+                grid.swapTiles(from, columnIndex, to, columnIndex);
+                const tempTile = vector[to];
+                vector[to] = vector[from];
+                vector[from] = tempTile;        
+            },
+            getLength: (grid) => grid.numColumns
         }
     } else if (direction === Direction.Left || direction === Direction.Right) {
         settings = {
             ...settings,
-            getVector: getRow,
-            swap: swapInRow,
-            getLength: getNumRows
+            getVector: (grid, index) => grid.getRow(index),
+            swap: (grid, vector, rowIndex, from, to) => {
+                grid.swapTiles(rowIndex, from, rowIndex, to);
+                const tempTile = vector[to];
+                vector[to] = vector[from];
+                vector[from] = tempTile;
+            },
+            getLength: (grid) => grid.numRows
         }
     }