Changing old var to let (No declaration issues)

index.html

@@ -68,7 +68,7 @@
     // game constants
     //-------------------------------------------------------------------------
 
-    var KEY     = { ESC: 27, SPACE: 32, LEFT: 37, UP: 38, RIGHT: 39, DOWN: 40 },
+    let KEY     = { ESC: 27, SPACE: 32, LEFT: 37, UP: 38, RIGHT: 39, DOWN: 40 },
         DIR     = { UP: 0, RIGHT: 1, DOWN: 2, LEFT: 3, MIN: 0, MAX: 3 },
         stats   = new Stats(),
         canvas  = get('canvas'),
@@ -84,7 +84,7 @@
     // game variables (initialized during reset)
     //-------------------------------------------------------------------------
 
-    var dx, dy,        // pixel size of a single tetris block
+    let dx, dy,        // pixel size of a single tetris block
         blocks,        // 2 dimensional array (nx*ny) representing tetris court - either empty block or occupied by a 'piece'
         actions,       // queue of user actions (inputs)
         playing,       // true|false - game is in progress
@@ -112,20 +112,20 @@
     //
     //-------------------------------------------------------------------------
 
-    var i = { size: 4, blocks: [0x0F00, 0x2222, 0x00F0, 0x4444], color: 'cyan'   };
-    var j = { size: 3, blocks: [0x44C0, 0x8E00, 0x6440, 0x0E20], color: 'blue'   };
-    var l = { size: 3, blocks: [0x4460, 0x0E80, 0xC440, 0x2E00], color: 'orange' };
-    var o = { size: 2, blocks: [0xCC00, 0xCC00, 0xCC00, 0xCC00], color: 'yellow' };
-    var s = { size: 3, blocks: [0x06C0, 0x8C40, 0x6C00, 0x4620], color: 'green'  };
-    var t = { size: 3, blocks: [0x0E40, 0x4C40, 0x4E00, 0x4640], color: 'purple' };
-    var z = { size: 3, blocks: [0x0C60, 0x4C80, 0xC600, 0x2640], color: 'red'    };
+    let i = { size: 4, blocks: [0x0F00, 0x2222, 0x00F0, 0x4444], color: 'cyan'   };
+    let j = { size: 3, blocks: [0x44C0, 0x8E00, 0x6440, 0x0E20], color: 'blue'   };
+    let l = { size: 3, blocks: [0x4460, 0x0E80, 0xC440, 0x2E00], color: 'orange' };
+    let o = { size: 2, blocks: [0xCC00, 0xCC00, 0xCC00, 0xCC00], color: 'yellow' };
+    let s = { size: 3, blocks: [0x06C0, 0x8C40, 0x6C00, 0x4620], color: 'green'  };
+    let t = { size: 3, blocks: [0x0E40, 0x4C40, 0x4E00, 0x4640], color: 'purple' };
+    let z = { size: 3, blocks: [0x0C60, 0x4C80, 0xC600, 0x2640], color: 'red'    };
 
     //------------------------------------------------
     // do the bit manipulation and iterate through each
     // occupied block (x,y) for a given piece
     //------------------------------------------------
     function eachblock(type, x, y, dir, fn) {
-      var bit, result, row = 0, col = 0, blocks = type.blocks[dir];
+      let bit, result, row = 0, col = 0, blocks = type.blocks[dir];
       for(bit = 0x8000 ; bit > 0 ; bit = bit >> 1) {
         if (blocks & bit) {
           fn(x + col, y + row);
@@ -141,7 +141,7 @@
     // check if a piece can fit into a position in the grid
     //-----------------------------------------------------
     function occupied(type, x, y, dir) {
-      var result = false
+      let result = false
       eachblock(type, x, y, dir, function(x, y) {
         if ((x < 0) || (x >= nx) || (y < 0) || (y >= ny) || getBlock(x,y))
           result = true;
@@ -157,11 +157,11 @@
     // start with 4 instances of each piece and
     // pick randomly until the 'bag is empty'
     //-----------------------------------------
-    var pieces = [];
+    let pieces = [];
     function randomPiece() {
       if (pieces.length == 0)
         pieces = [i,i,i,i,j,j,j,j,l,l,l,l,o,o,o,o,s,s,s,s,t,t,t,t,z,z,z,z];
-      var type = pieces.splice(random(0, pieces.length-1), 1)[0];
+      let type = pieces.splice(random(0, pieces.length-1), 1)[0];
       return { type: type, dir: DIR.UP, x: Math.round(random(0, nx - type.size)), y: 0 };
     }
 
@@ -175,7 +175,7 @@
       showStats(); // initialize FPS counter
       addEvents(); // attach keydown and resize events
 
-      var last = now = timestamp();
+      let last = now = timestamp();
       function frame() {
         now = timestamp();
         update(Math.min(1, (now - last) / 1000.0)); // using requestAnimationFrame have to be able to handle large delta's caused when it 'hibernates' in a background or non-visible tab
@@ -213,7 +213,7 @@
     }
 
     function keydown(ev) {
-      var handled = false;
+      let handled = false;
       if (playing) {
         switch(ev.keyCode) {
           case KEY.LEFT:   actions.push(DIR.LEFT);  handled = true; break;
@@ -285,7 +285,7 @@
     }
 
     function move(dir) {
-      var x = current.x, y = current.y;
+      let x = current.x, y = current.y;
       switch(dir) {
         case DIR.RIGHT: x = x + 1; break;
         case DIR.LEFT:  x = x - 1; break;
@@ -303,7 +303,7 @@
     }
 
     function rotate() {
-      var newdir = (current.dir == DIR.MAX ? DIR.MIN : current.dir + 1);
+      let newdir = (current.dir == DIR.MAX ? DIR.MIN : current.dir + 1);
       if (unoccupied(current.type, current.x, current.y, newdir)) {
         current.dir = newdir;
         invalidate();
@@ -331,7 +331,7 @@
     }
 
     function removeLines() {
-      var x, y, complete, n = 0;
+      let x, y, complete, n = 0;
       for(y = ny ; y > 0 ; --y) {
         complete = true;
         for(x = 0 ; x < nx ; ++x) {
@@ -351,7 +351,7 @@
     }
 
     function removeLine(n) {
-      var x, y;
+      let x, y;
       for(y = n ; y >= 0 ; --y) {
         for(x = 0 ; x < nx ; ++x)
           setBlock(x, y, (y == 0) ? null : getBlock(x, y-1));
@@ -362,7 +362,7 @@
     // RENDERING
     //-------------------------------------------------------------------------
 
-    var invalid = {};
+    let invalid = {};
 
     function invalidate()         { invalid.court  = true; }
     function invalidateNext()     { invalid.next   = true; }
@@ -385,7 +385,7 @@
         ctx.clearRect(0, 0, canvas.width, canvas.height);
         if (playing)
           drawPiece(ctx, current.type, current.x, current.y, current.dir);
-        var x, y, block;
+        let x, y, block;
         for(y = 0 ; y < ny ; y++) {
           for (x = 0 ; x < nx ; x++) {
             if (block = getBlock(x,y))
@@ -399,7 +399,7 @@
 
     function drawNext() {
       if (invalid.next) {
-        var padding = (nu - next.type.size) / 2; // half-arsed attempt at centering next piece display
+        let padding = (nu - next.type.size) / 2; // half-arsed attempt at centering next piece display
         uctx.save();
         uctx.translate(0.5, 0.5);
         uctx.clearRect(0, 0, nu*dx, nu*dy);