Wanted to get feedback on a series of complexities I've been hitting with standard and async iterators. Basically it's hard atm to write functions that uses async iterators to do specific operations. Here is an example:
Return the first item in an iterator
async function peek () {
for await (const data of createIterator()) {
return data
}
throw new Error('Not found')
}This results in Invalid loop. Its body allows only one iteration.. Unless someone knows a better pattern the way to write the equivalent in standard friendly syntax is
const ite = createIterator()[Symbol.asyncIterator]()
try {
const next = await ite.next()
if (!next.done) return next.value
} finally {
await ite.return()
}
throw new Error('Not found')Personally I find the first version much more readable and understandable.
Equivally I've had issues making assertions in tests with async iterators, like "check if this iterator returns any values" as that runs into "data is defined but never used" lints, ie:
async function assertEmpty (t) {
for await (const data of iterator) {
t.fail('should be empty')
return
}
}I don't know if there is any ESlint specific rules to async loops to make this easier, but wanted to share to hear if anyone was running into the same kind of issues.
Wanted to get feedback on a series of complexities I've been hitting with standard and async iterators. Basically it's hard atm to write functions that uses async iterators to do specific operations. Here is an example:
Return the first item in an iterator
This results in
Invalid loop. Its body allows only one iteration.. Unless someone knows a better pattern the way to write the equivalent in standard friendly syntax isPersonally I find the first version much more readable and understandable.
Equivally I've had issues making assertions in tests with async iterators, like "check if this iterator returns any values" as that runs into "data is defined but never used" lints, ie:
I don't know if there is any ESlint specific rules to async loops to make this easier, but wanted to share to hear if anyone was running into the same kind of issues.