What is the difference between channel.fori and channel.consumeEach ?

# coroutines

[myanmarking]

What is the difference between channel.fori and channel.consumeEach ?

[Sam]

consumeEach will call cancel() on the channel after you're done iterating. The main situation where that differs from a regular for loop is if the iteration ends early, for example due to an exception or control flow statement in the loop body. A for loop can stop iterating while leaving the channel open for future items, but consumeEach will always leave the channel in a closed state.

[Sam]

If the iteration just runs without interruption until the channel is closed, there's no real difference between the two approaches.

[myanmarking]

what does it mean: ‘consumeEach’ will cancel? consumeEach won’t return until the sender closes the channel

[myanmarking]

what is the meaning of a consumer closing the channel. this part i dont get

[Sam]

A channel can be closed either by the sender calling close() or by the consumer calling cancel(). You're right that consumeEach won't normally return until the sender closes the channel, but there are cases where that's not true. For example:

channel.consumeEach {
    throw Exception("There was an error")
}

If an exception is thrown from consumeEach, the iteration stops and won't process any more items. In that case, the consumeEach function will automatically call cancel() to close the channel before letting the error propagate.

[myanmarking]

oh ok. now i get it. Thanks! the docs don’t state that