misdeed
Promise-based task management with abortion.
Requires native support for Promise, const and let.
Installation
npm install misdeed
API
new misdeed.Task(executor)
Creates a new task, to be performed by executor. Each task has a .promise
property containing a promise for when the task is completed. The executor is
called with resolve and reject arguments to either fulfill or reject this
promise.
The executor may return an abort handler which will be called when the task is
aborted. It'll only be called once, and only if the .promise is still pending.
How abortion is handled, if at all, is left to the executor. The executor may
chose to fulfill or reject the promise, or leave it pending.
Note that if the executor calls resolve() with another pending promise its
abort handler may still be called until that promise settles. And since promise
state cannot be observed synchronously race conditions may occur where the abort
handler is called after resolving the promise, but before that change could be
observed.
Each task has a .aborted property containing a promise for when the task is
aborted. This may never happen, in which case the promise will never settle.
Tasks can be aborted by calling .abort(). If the executor did not return an
abort handler, or the .promise has already (been observed to have) settled,
the .aborted promise is fulfilled with false. If the abort handler throws an
error that error is used to reject the .aborted promise. Otherwise the
.aborted promise is fulfilled with true. The .aborted promise is returned
when calling .abort().
Note that even if the .aborted promise is fulfilled with true the .promise
may still settle.
misdeed.Task#abortAfter(delay)
Aborts the task after the delay, specified in milliseconds. setTimeout is used
internally. Consequently the task may be aborted a little sooner or a little
later than specified.
Returns an object with a .aborted property, containing the .aborted property
of the task. Additionally the handle returned by setTimeout is available on
the returned object as .timer. In io.js you could call
unref() on the timer so it
won't unnecessarily keep the program running. Please read the io.js
documentation carefully, caveat emptor.
misdeed(Promise)
Returns an object with a new Task constructor, which uses the value of
Promise to construct the .promise and .aborted promises. This lets you use
Misdeed with non-native Promise implementations.
License
ISC