javascript - 如何在中断 "for await"循环后*重新打开* AsyncIterator？

Question

在函数中 testMultipleLoops2第一个之后for await , l将转向GeneratorStatus:<closed> ,我进行了大量研究，但没有找到重新打开它的方法。

const tryRecursive=async function*(i=0){console.count("tryRecursive");yield i++;yield*tryRecursive(i)}
const asyncDelay=(b,delay=1e3)=>new Promise((resolve,reject)=>setTimeout(()=>resolve(b()),delay))
const tryDelayYieldNumbers=async function*(){
  for await(const i of tryRecursive()){
    const result=await asyncDelay(()=>i)
    yield result}}
const testMultipleLoops2=(async()=>{
  const l=tryDelayYieldNumbers()
  let count=3
  for await(const i of l){if(count-->0)console.log(i);else break}
  count=4
  ///But `l` is closed here, can't do future looping
  for await(const i of l){if(count-->0)console.log(i);else break}
  count=5
  for await(const i of l){if(count-->0)console.log(i);else break}
})()

Answer 1

你要求的是不可能的。通过设计(并根据语言规范)，即使您使用 break 提前终止循环。

参见 https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...of#Closing_iterators