Check for check

src/index.js

@@ -280,6 +280,35 @@ class Board extends React.Component {
     return moves;
   }
 
+  inCheck() {
+    var blackKing = null;
+    var whiteKing = null;
+    for(var i = 0; i < this.state.squares.length; i++) {
+      if(this.state.squares[i] === Pieces.BlackKing) {
+        blackKing = this.getXandY(i);
+      } else if(this.state.squares[i] === Pieces.WhiteKing) {
+        whiteKing = this.getXandY(i);
+      }
+    }
+
+    for(i = 0; i < this.state.squares.length; i++) {
+      let moves = this.getValidMoves(i);
+      for(var j = 0; j < moves.length; j++) {
+        if(moves[j][0] === blackKing[0] && moves[j][1] === blackKing[1]) {
+          return true;
+        } else if(moves[j][0] === whiteKing[0] && moves[j][1] === whiteKing[1]) {
+          return true;
+        }
+      }
+    }
+
+    return false;
+  }
+
+  checkmate() {
+    return false;
+  }
+
   getValidMoves(source) {
     let [x, y] = this.getXandY(source);
     console.log([x, y]);
@@ -376,9 +405,10 @@ class Board extends React.Component {
 
   render() {
     const winner = calculateWinner(this.state.squares);
+    let checkMsg = this.inCheck() ? "Check! " : "";
     let status = winner ?
       'Winner: ' + winner :
-      (this.state.blackIsNext ? 'Black' : 'White') + "'s Turn";
+      checkMsg + (this.state.blackIsNext ? 'Black' : 'White') + "'s Turn";
 
     var texttext =
       <div style={{textAlign: `center`,}}>
@@ -391,6 +421,7 @@ class Board extends React.Component {
         {this.row(5)}
         {this.row(6)}
         {this.row(7)}
+        {this.inCheck()}
       </div>
     ;