javascript - settimeout 并等待(如果已设置超时)

Question

如何为settimeout函数创建队列。

我想创建带有 settimeout 的函数以在 2 秒后打印控制台，但如果相同的 settimeout 已经在等待执行，则应在完成第一个函数后执行新的超时函数

<script>
function print_console(text,time)
{
   if(timeout is not already set)
   {
      timeout=setTimeout(function(){console.log(text);},time);
   }
   else
   {
     time=addition of time of already setted timeout + argument time
     timeout=setTimeout(function(){console.log(text);},time);
   }
}
print_console('i will print in 1000 minisec',1000);
print_console('i will print in 3000 minisec',2000);
print_console('i will print in 6500 minisec',3500);
.................
.............
</script>

我期望此函数在控制台输出屏幕上输出--

我将在 1000 微秒内打印 --- 07/08/2019 04:01:01

我将在 3000 微秒内打印 --- 07/08/2019 04:01:03

我将在 6500 微秒内打印 --- 07/08/2019 04:01:06

Answer 1

您可以为此使用async/await:

(async () => { 
  async function print_console(text,time) {
    await new Promise((res, rej) => {
      setTimeout(() => (console.log(text), res()), time);
    });
  }

  await print_console('i will print in 1000 minisec',1000);
  await print_console('i will print in 3000 minisec',2000);
  await print_console('i will print in 6500 minisec',3500);
})();

---

编辑:OP想要在此范围之外调用它。然后我会使用另一种方法，使用 IFEE 将数组、标志 var 和函数调用者存储到函数作用域中:

const print_console = (() => {
  const arr = [];
  let isProcessing = false;
  
  setInterval(() => {
    if(isProcessing) return;
    
    const next = arr.shift();
    if(next) {
      isProcessing = true;
      setTimeout(() => {
        console.log(next.text);
        isProcessing = false;
      }, next.time);
    }
  });
  
  return (text, time) => {
      arr.push({text, time});
  } 
})();


print_console('i will print in 1000 minisec',1000);
print_console('i will print in 3000 minisec',2000);
print_console('i will print in 6500 minisec',3500);