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E.when
Turadg Aleahmad edited this page Apr 4, 2023
·
2 revisions
Use E.when(promise, onfulfilled)
instead of promise.then(onfulfilled)
.
E.when
produces tracking info necessary for our deep stacks. .then
, .catch
, .finally
, and await
do not.
Keep in mind that the onrejected
param to E.when
handles only rejection of promise argument. If you want a single rejection handler like the Promise provides,
promise.then(onfulfilled).catch(onrejected)
then use the promise returned by E.when
,
E.when(p, onfulfilled).catch(onrejected)
Note that E.when(p, onfulfilled).catch(onrejected)
still loses tracking info compared to
E.when(
E.when(p, onfulfilled),
undefined,
onrejected
)
Bear in mind that handler of the primary promise may reject as well. These will catch rejections in onFulfilled:
p.then(onFulfilled).catch(onRejected);
E.when(
E.when(p, onfulfilled),
undefined,
onrejected
);
…and these won't:
p.then(onFulfilled, onRejected);
E.when(p, onFulfilled, onRejected);
This wiki is for developing agoric-sdk. For help using Agoric SDK, see https://docs.agoric.com/ and https://agoric-sdk.pages.dev/