Closed tcf909 closed 4 years ago
I would imagine yield
would behave identically to await
in this case.
Early testing showed otherwise...which is why I was confused.
I'll post some working examples, but basically upon returning from a yield a Fiber was still available via Fiber.current
It depends on if the original stack has unwound. await
will always run on a clean stack but yield
might not.
It seems to maintain the original stack -- very interesting. Wonder if there is risk of this breaking in the future. Thoughts?
Test code:
const Sync = require('@digitalspaces/syncho');
Sync(() => {
function* test(v){
while(true){
Sync.wait(cb => setTimeout(cb, 100));
yield v;
Sync.wait(cb => setTimeout(cb, 100));
if( ! require('fibers').current )
throw new Error();
console.log(new Error());
/* Output--------------->
Error
at test (/Users/tc.ferguson/Sync/Workspace/MyDigitalSpaces/benchmarks/test2.js:26:16)
at test.next (<anonymous>)
at /Users/tc.ferguson/Sync/Workspace/MyDigitalSpaces/benchmarks/test2.js:33:13
*/
}
}
for( const v of test()){
console;
}
});
I recommend trying without fibers to get a better sense of how generators work.
function* gen() {
for (;;) {
console.trace();
yield;
}
}
const foo = gen();
foo.next();
process.nextTick(() => foo.next());
Logs:
Trace
at gen (/Users/marcel/a.js:3:11)
at gen.next (<anonymous>)
at Object.<anonymous> (/Users/marcel/a.js:9:5)
at Module._compile (internal/modules/cjs/loader.js:959:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:995:10)
at Module.load (internal/modules/cjs/loader.js:815:32)
at Function.Module._load (internal/modules/cjs/loader.js:727:14)
at Function.Module.runMain (internal/modules/cjs/loader.js:1047:10)
at internal/main/run_main_module.js:17:11
Trace
at gen (/Users/marcel/a.js:3:11)
at gen.next (<anonymous>)
at /Users/marcel/a.js:10:28
at processTicksAndRejections (internal/process/task_queues.js:75:11)
If you unwind from a fiber you won't be in a fiber anymore.
@laverdet Any issues with using Fibers with generators and yield that you know of? I know with await there is an issue getting back into a Fiber after awaiting. Anything similar you've run across with generators and yield?
I've tested a bunch of scenarios and everything seems fine, but I have a big implementation to do based on generators and wanted to double check with you before I get too far down the path.
Thanks