square.js:70 Uncaught TypeError: Cannot read property '0' of undefined
at Square3.Square.rotate (square.js:70)
at Game.rotate (game.js:89)
at HTMLDocument.document.onkeydown (local.js:23)
试理解执行顺序：
刷新页面：init()【game.js】>>cur = SquareFactory.prototype.make(2,2,)【game.js】>>s.rotate(2)【squareFactory.js】>>rotate(num)【square.js】;
按上箭头键 : Game.rotate()【local.js】>>cur.rotate()【game.js】>>rotate(num)【square.js】;
疑惑：最后执行旋转到底有没有参数，假如有参数是哪一步赋值的？
楼下为我写的代码：
Square.prototype.canRotate = function (isValid) {
var tsPoints = this.orgPoints;
var tsCodes;
var tsDrt = (this.drt + 1) % 4;
tsCodes = [
[0, 0, 0, 0],
[0, 0, 0, 0],
[0, 0, 0, 0],
[0, 0, 0, 0]
];
for (var i = 0; i < this.squCodes.length; i++) {
for (var j = 0; j < this.squCodes[0].length; j++) {
tsCodes[i][j] = this.rotCodes[tsDrt][i][j];
}
}
return isValid(tsPoints, tsCodes);
};
Square.prototype.rotate = function (num) {
if (!num) {
mum = 1;
}
this.drt = (this.drt + num) % 4;
for (var i = 0; i < this.squCodes.length; i++) {
for (var j = 0; j < this.squCodes[0].length; j++) {
this.squCodes[i][j] = this.rotCodes[this.drt][i][j];
}
}
};