如何每秒输出一个索引中的每个数字? [英] How to output each number consecutively in an index every second?

问题描述

我有以下循环:

for (let index = 0; index < 4; index++) {  
  setInterval(function() {
    console.log(index)
  }, 1000);
}

如何使控制台记录0到第一秒，1到第二秒，2到第三秒，3到第四秒，0到第五秒，依此类推，直到清除间隔?

How can I make it so that it console logs 0 the first second, 1 the second second, 2 the third second, 3 the fourth second, 0 the fifth second, and so on until the interval is cleared?

推荐答案

这是使用生成器函数的一种或多或少但更优雅的解决方案.

Here's a more-or-less-but-rather-more elegant solution using a generator function.

生成器函数在这里很有用，因为它们的执行可以通过 yield 暂停，并通过调用生成器对象的 next 方法恢复执行:

Generator functions are useful here, as their execution can be paused by yield, and resumed by calling the generator object's next method:

function* logger() {
  while (true) {
    for (let index = 0; index < 4; index++) {
      console.log(index)
      yield
    }
  }
}

let generator = logger()
setInterval(() => generator.next(), 1000)

或者，再次使用生成器，您甚至可以 yield 当前的 index ，并让interval函数记录日志(或执行其他任何操作):

Or, again with generators, you can even yield the current index, and let the interval function log (or do anything else with) it:

function* logger() {
  while (true) {
    for (let index = 0; index < 4; index++) {
      yield index
    }
  }
}

let generator = logger()
setInterval(() => console.log(generator.next().value), 1000)

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