I'm experimenting with promises - namely when.js - and want to convert some test code - a little unclear how to do it even after reading docs. My experiments so far have been far messier than standard callback pyramids so I think I am missing some shortcut.
Here's my sample code I would like to replicate:
Async1(function(err, res) {
res++;
Async2(res, function(error, result) {
done();
})
})
nodefn.call(Async2, nodefn.call(Async1)).ensure(done);
Here, Async2
actually gets called synchronously and with the Promise for Async1()
as an argument - it doesn't wait for Async1
to resolve. To chain them, you would need to use
nodefn.call(Async1).then(nodefn.lift(Async2)).ensure(done);
// which is equivalent to:
nodefn.call(Async1).then(function(result) {
return nodefn.call(Async2, result);
}).ensure(done);
I want to perform some logic between the 2 calls
Then you would need to put another function in the chain, or modify one of the functions in the chain:
nodefn.call(Async1)
.then(function(res){return res+1;}) // return modified result
.then(nodefn.lift(Async2))
.ensure(done);
// or just
nodefn.call(Async1).then(function(res) {
res++; // do whatever you want
return nodefn.call(Async2, res);
}).ensure(done);