From a83829e2aa3567cba157e4a632ccb3031c529c6c Mon Sep 17 00:00:00 2001
From: Sage Vaillancourt <sagev9000@tutanota.com>
Date: Wed, 30 Dec 2020 10:08:18 -0500
Subject: [PATCH] Add small helper functions

---
 src/index.js | 53 ++++++++++++++++++++++++++++++----------------------
 1 file changed, 31 insertions(+), 22 deletions(-)

diff --git a/src/index.js b/src/index.js
index bf96000..06c5881 100644
--- a/src/index.js
+++ b/src/index.js
@@ -135,14 +135,15 @@ class Board extends React.Component {
       new Piece(BLACK, KNIGHT),
       new Piece(BLACK, ROOK)
     ];
+    function add(num, color, type) {
+      for(var i = 0; i < num; i++) {
+        squares.push(new Piece(color, type));
+      }
+    }
     let squares = whiteRow;
-    for(var i = 0; i < 8; i++) {
-      squares.push(new Piece(WHITE, PAWN));
-    }
+    add(8, WHITE, PAWN);
     squares = squares.concat(Array(32).fill(null));
-    for(i = 0; i < 8; i++) {
-      squares.push(new Piece(BLACK, PAWN));
-    }
+    add(8, BLACK, PAWN);
     squares = squares.concat(blackRow);
 
     return squares;
@@ -154,10 +155,18 @@ class Board extends React.Component {
     return [x, y];
   }
 
+  getIndex(x, y) {
+    return x + (y * 8);
+  }
+
+  isValidXY(x, y) {
+    return x < 8 && x >=0 && y < 8 && y >= 0;
+  }
+
   pieceAt(x, y) {
-    let i = x + (y * 8);
-    if (i < 64 && x < 8 && y < 8 && x >= 0 && y >= 0) {
-      return this.state.squares[x + (y * 8)];
+    let i = this.getIndex(x, y);
+    if (i < 64 && this.isValidXY(x, y)) {
+      return this.state.squares[this.getIndex(x, y)];
     } else {
       return null;
     }
@@ -188,15 +197,17 @@ class Board extends React.Component {
     var i;
     var moves = [];
     let tryAddMove = (x, y) => {
-      if (x >= 0 && x < 8 && y >= 0 && y < 8 && this.pieceAt(x, y) == null) {
-        moves.push({x: x, y: y});
-        // Keep searching
-        return 0;
-      } else if (this.isEnemyOf(piece, x, y)) {
-        moves.push({x: x, y: y});
+      if (this.isValidXY(x, y)) {
+        if(this.pieceAt(x, y) == null) {
+          moves.push({x: x, y: y});
+          // Keep searching
+          return 0;
+        } else if (this.isEnemyOf(piece, x, y)) {
+          moves.push({x: x, y: y});
+        }
+        // Stop searching
+        return 1;
       }
-      // Stop searching
-      return 1;
     };
 
     if (isPawn(piece)) {
@@ -208,7 +219,7 @@ class Board extends React.Component {
       let left = this.pieceAt(x - 1, y);
       let right = this.pieceAt(x + 1, y);
       if (left != null && left.passantable && left.color !== piece.color) {
-        moves.push({x:x - 1, y:y + shift, passant: {x: x - 1, y: y}})
+        moves.push({x: x - 1, y: y + shift, passant: {x: x - 1, y: y}})
       }
       if (right != null && right.passantable && right.color !== piece.color) {
         moves.push({x: x + 1, y: y + shift, passant: {x: x + 1, y: y}})
@@ -222,7 +233,7 @@ class Board extends React.Component {
         }
       }
       [x + 1, x - 1].forEach(x => {
-        if (x >= 0 && x < 8 && this.isEnemyOf(piece, x, y + shift)) {
+        if (this.isValidXY(x, y + shift) && this.isEnemyOf(piece, x, y + shift)) {
           moves.push({x: x, y: y + shift});
         }
       });
@@ -393,9 +404,7 @@ class Board extends React.Component {
     let [destX, destY] = this.getXandY(dest);
 
     for (var move of this.getValidMoves(source)) {
-      let x = move.x;
-      let y = move.y;
-      if (destX === x && destY === y) {
+      if (destX === move.x && destY === move.y) {
         return move;
       }
     }