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async waterfall
8 CommentsSorted by Oldest First
I've actually implemented a quick and dirty version of waterfall in one of our collection hooks:
```function waterfall (functions, callback) {
var execute = function (functions, lastResult) {
if(!functions.length){
callback(null, lastResult);
}else{
functions[0](lastResult, function(error, newResult) {
execute(functions.slice(1), newResult);
});
}
};
//first function takes only a callback
functions[0]( function (error, result){
execute(functions.slice(1), result);
});
}```
However, promises (used in the javascript sdk) are generally awesome, and coincidentally all but eliminate the need for "waterfall" once you convert callback-based code to being promise-based. If you have access to a working version of the BL CLI (http://devcenter.kinvey.com/nodejs/tutorials/business-logic-revisions), I'd **highly** recommend investing time in add a good promises library to "common code", and converting as much of your BL to be promise-based as humanly possible (we plan to do this as soon as a CLI issue on Ubuntu is ironed out)
```function waterfall (functions, callback) {
var execute = function (functions, lastResult) {
if(!functions.length){
callback(null, lastResult);
}else{
functions[0](lastResult, function(error, newResult) {
execute(functions.slice(1), newResult);
});
}
};
//first function takes only a callback
functions[0]( function (error, result){
execute(functions.slice(1), result);
});
}```
However, promises (used in the javascript sdk) are generally awesome, and coincidentally all but eliminate the need for "waterfall" once you convert callback-based code to being promise-based. If you have access to a working version of the BL CLI (http://devcenter.kinvey.com/nodejs/tutorials/business-logic-revisions), I'd **highly** recommend investing time in add a good promises library to "common code", and converting as much of your BL to be promise-based as humanly possible (we plan to do this as soon as a CLI issue on Ubuntu is ironed out)
sorry about the formatting, here's a gist: https://gist.github.com/micmarsh/f9cecb02af47d3bdfe3c
oh wow I totally missed the "common code" section of that doc.
I actually kept getting frustrated not being able to use promises... yeah, guess I should add one there.
Thanks!
I actually kept getting frustrated not being able to use promises... yeah, guess I should add one there.
Thanks!
No problem, glad to be of help! :-)
have you had any luck loading a library into utils?
I can't even get the example they have to work.
I can't even get the example they have to work.
I'm still waiting for a working Ubuntu version of the CLI, but I'll let you know if and when I am able to try something!
I tried it today with Q but setTimeout isn't supported so the whole thing just ends up failing.
Not really sure where to go with this when any setTimeout usage kills it.
Not really sure where to go with this when any setTimeout usage kills it.
Ah, I haven't been able to try anything yet since I'm still waiting on a fix for the Ubuntu CLI. At this point, I would just start searching github for promise libraries and making sure they don't have setTimeout anywhere :-/
Michael LeBarron