递归循环中出现意外值

Question

我有一个递归循环，对于这个问题，我已经简化为以下内容：

const move = (gameGrid) => {
if (Math.random() > 0.2) return false;
let newGameGrid = [...gameGrid];
return newGameGrid;
}
const play = (initGrid) => {
for (let player1Move=0; player1Move<9; player1Move++) {
grid1 = move(initGrid);
if (!grid1) continue;
for (let player2Move=0; player2Move<9; player2Move++) {
// Why is grid1 sometimes false here???
grid2 = move(grid1);
if (!grid2) continue;
play(grid2);
}
}
}
play([])

如果运行此程序，您会注意到，有时在第二个play()循环中，对move(grid1)的调用在[...gameGrid]失败，因为grid1为false。然而，这应该是不可能的，因为在第二个循环执行之前，grid1被检查为假值。

你知道我在这里错过了什么吗？我猜grid1正在被覆盖，但我不确定如何覆盖或在哪里覆盖。

Answer 1

不确定您想要实现什么，但看起来您还没有在范围中定义grid1和grid2，它们在递归函数调用期间在

全局范围

const move = (gameGrid) => {
if (Math.random() > 0.2) return false;
let newGameGrid = [...gameGrid];
return newGameGrid;
}
const play = (initGrid) => {
for (let player1Move = 0; player1Move < 9; player1Move++) {
let grid1 = move(initGrid);
if (!grid1) continue;
for (let player2Move = 0; player2Move < 9; player2Move++) {
// Why is grid1 sometimes false here???
let grid2 = move(grid1);
if (!grid2) continue;
play(grid2);
}
}
}
play([])