Allows libraries to handle various caller provided asynchronous functions uniformly. Maps promises, observables, child processes and streams, and callbacks to callback style.
As async conventions evolve, it is useful to be able to deal with several different styles of async completion uniformly. With this module you can handle completion using a node-style callback, regardless of a return value that's a promise, observable, child process or stream.
var asyncDone = require('async-done');
asyncDone(function(done){
// do async things
done(null, 2);
}, function(error, result){
// `error` will be null on successful execution of the first function.
// `result` will be the result from the first function.
});var asyncDone = require('async-done');
asyncDone(function(done){
// do async things
done(new Error('Some Error Occurred'));
}, function(error, result){
// `error` will be an error from the first function.
// `result` will be undefined on failed execution of the first function.
});Takes a function to execute (fn) and a function to call on completion (callback).
Optionally takes a callback to call when async tasks are complete.
Callback(done) called- Completion: called with null error
- Error: called with non-null error
StreamorEventEmitterreturned- Completion: end-of-stream module
- Error: domains
- Note: Only actual streams are supported, not faux-streams; Therefore, modules like
event-streamare not supported.
Child Processreturned- Completion end-of-stream module
- Error: domains
Promisereturned- Completion: onFulfilled method called
- Error: onRejected method called
Observable(e.g. from RxJS v5 or RxJS v4) returned- Completion: [complete][rxjs5-subscriber-complete] method called
- Error: [error][rxjs5-subscriber-error] method called
Warning: Sync tasks are not supported and your function will never complete if the one of the above strategies is not used to signal completion. However, thrown errors will be caught by the domain.
If an error doesn't occur in the execution of the fn function, the callback method will receive the results as its second argument. Note: Some streams don't received any results.
If an error occurred in the execution of the fn function, The callback method will receive an error as its first argument.
Errors can be caused by:
- A thrown error
- An error passed to a
donecallback - An
errorevent emitted on a returnedStream,EventEmitterorChild Process - A rejection of a returned
Promise- If thePromiseis not rejected with a value, we generate a newError - The
onErrorhandler being called on anObservable
MIT
