如何在每个循环中添加变量？

let sum = 0;
for (let i = 0; i < 10; i++) {
  sum += i;
}
console.log(sum); // 输出45

numbers = []
for i in range(10):
  numbers.append(i)
print(numbers) # 输出[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

for (let i = 0; i < 10; i++) {
  (function(index) {
    setTimeout(function() {
      console.log(index);
    }, 1000);
  })(i);
}