javascript - setInterval 内的 setTimeout 循环

Question

我有类似的代码:

var count = 0;

setInterval(function() {
  if(count===0){
    console.log(123);
    count++;
  } else if(count>0) {
    for(i=1;i<=2;i++){
        (function(ind) {
            setTimeout(function() {
              console.log(ind);
            }, 1000 * ind);
        })(i);
    }
    count=0;
  }
},1000)

结果不是我所期望的，我希望控制台日志实现的效果如下:

123
1
2
123
1
2
...

以此类推，每个间隔为 1000ms。另外我想问一下有没有更好的方法呢？ setTimeout 循环的数量(上述情况为 2)每次可以/可能不同。

Answer 1

something like this, first print 123 and wait for 1000ms, then 1 and wait for 1000ms, finally 2 and wait for 1000ms after that repeat the whole process infinitely

如果您希望以 1000 毫秒的间隔定期执行，并进行内部倒计时然后重置，则可以仅使用单个 setInterval:

// Uses a 100ms rather than 1000ms counter, stopping after two seconds
var count = 0;
var inner = 0;
var handle = setInterval(function() {
  if (inner == 0) {
    // Start again
    console.log(123);
    count = 0;
    // The number of "inner" counts to do
    inner = 2;
  } else {
    // An "inner" count
    ++count;
    --inner;
    console.log(count);
  }
}, 100);

// Stop it after two seconds, just for demo purposes
setTimeout(function() {
  clearInterval(handle);
}, 2000);