async exits with streamline

gistfile1.js

//this does not work because exists does not accept a standard callback

    function createRequiredFilesIfNotPresent(_) {
        var baseFolder = process.cwd();
        var exists = path.exists(baseFolder + "/server.js");
        log.info(exists);
    }


//using a wrapper function however works. Log entries added for sequence.

    function exists(p, callback) {
        path.exists(p, function(e) {
            callback(null, e);
        });
    }

    function createRequiredFilesIfNotPresent(_) {
        var baseFolder = process.cwd();
        log.info("check exists start");
        var p1 = exists(baseFolder + "/server.js", _);
        log.info("exists:" + p1);
        log.info("check exists complete");
    }

Hi Glenn,

Yes, the vast majority of node callback based core APIs take a standard callback. path.exist is an exception and the little exists wrapper that you wrote is the way to deal with it.

There is also another gotcha with core APIs: the "futures" feature does not work directly with them, it only works with the functions that you have written in streamline.

One remark: you should swap lines 20 and 21. Also you can directly write:

log info("exists: " + exists(baseFolder + "/server.js", _));

Thanks Bruno Why not just include the exists wrapper in Streamline? Seems like it would be generally useful no? Nice work on Streamline.

…

On Mon, Apr 16, 2012 at 2:33 AM, Bruno Jouhier < ***@***.*** > wrote: Hi Glenn, Yes, the vast majority of node callback based core APIs take a standard callback. `path.exist` the exception and the little `exists` wrapper that you wrote is the way to deal with it. There is also another gotcha with core APIs: the "futures" feature does not work directly with them, it only works with the functions that you have written in streamline. One remark: you should swap lines 20 and 21. Also you can directly write: ``` javascript log info("exists: " + exists(baseFolder + "/server.js", _)); ``` --- Reply to this email directly or view it on GitHub: https://gist.github.com/2394695

Yes, I could provide a small library with it, or at least document it. I want to write a FAQ but I keep getting dragged into other things, like blog articles.

I don't want to put it directly into streamline's runtime though because I want to keep streamline at the language level. It runs in the browser too.

good point. Then a small add-on maybe of common streamline helpers would be very cool.

…

On Mon, Apr 16, 2012 at 1:07 PM, Bruno Jouhier < ***@***.*** > wrote: Yes, I could provide a small library with it, or at least document it. I want to write a FAQ but I keep getting dragged into other things, like blog articles. I don't want to put it directly into streamline's runtime though because I want to keep streamline at the language level. It runs in the browser too. --- Reply to this email directly or view it on GitHub: https://gist.github.com/2394695

Yes.

I have bundled a helper for streams because streams have an event API that does not work too well with streamline. So I have introduced a callback API on top of it that works much better with streamline. I did it because this is a non trivial thing and it makes a big difference in usability.

But I did not take care of all the corner cases of the node API. I could introduce a nodeutils module with other wrappers. I'll do it when I get time.

I track all this through the GitHub issues system. So if you want to enter the suggestion there please do it. Otherwise, I'll do it.

Bruno

I'd be happy to do a PR if you have a repo :-)

…

On Tue, Apr 17, 2012 at 4:28 AM, Bruno Jouhier < ***@***.*** > wrote: Yes. I have bundled a helper for streams because streams have an _event_ API that does not work too well with streamline. So I have introduced a _callback_ API on top of it that works much better with streamline. I did it because this is a non trivial thing and it makes a big difference in usability. But I did not take care of all the corner cases of the node API. I could introduce a `nodeutils` module with other wrappers. I'll do it when I get time. I track all this through the GitHub issues system. So if you want to enter the suggestion there please do it. Otherwise, I'll do it. Bruno --- Reply to this email directly or view it on GitHub: https://gist.github.com/2394695

It's https://github.com/Sage/streamlinejs Just file an "issue". I like to have things filed here because I like "closing" issues, and this one should be an easy one :-) BTW, I work for Sage, we compete in the business apps sphere but we also partner with MS at many levels. Bruno 2012/4/17 Glenn Block < [email protected]

…

I'd be happy to do a PR if you have a repo :-) On Tue, Apr 17, 2012 at 4:28 AM, Bruno Jouhier < ***@***.*** > wrote: > > Yes. > > I have bundled a helper for streams because streams have an _event_ API > that does not work too well with streamline. So I have introduced a > _callback_ API on top of it that works much better with streamline. I did > it because this is a non trivial thing and it makes a big difference in > usability. > > But I did not take care of all the corner cases of the node API. I could > introduce a `nodeutils` module with other wrappers. I'll do it when I get > time. > > I track all this through the GitHub issues system. So if you want to > enter > the suggestion there please do it. Otherwise, I'll do it. > > Bruno > --- > > Reply to this email directly or view it on GitHub: > https://gist.github.com/2394695 --- Reply to this email directly or view it on GitHub: https://gist.github.com/2394695

great. We should do a Skype chat :-) We're using streamline btw on a module we are developing. On Tue, Apr 17, 2012 at 1:16 PM, Bruno Jouhier < [email protected]

…

wrote: It's https://github.com/Sage/streamlinejs Just file an "issue". I like to have things filed here because I like "closing" issues, and this one should be an easy one :-) BTW, I work for Sage, we compete in the business apps sphere but we also partner with MS at many levels. Bruno 2012/4/17 Glenn Block < ***@***.*** > I'd be happy to do a PR if you have a repo :-) > > On Tue, Apr 17, 2012 at 4:28 AM, Bruno Jouhier < > ***@***.*** > > > wrote: > > > > Yes. > > > > I have bundled a helper for streams because streams have an _event_ API > > that does not work too well with streamline. So I have introduced a > > _callback_ API on top of it that works much better with streamline. I > > did > > it because this is a non trivial thing and it makes a big difference in > > usability. > > > > But I did not take care of all the corner cases of the node API. I > > could > > introduce a `nodeutils` module with other wrappers. I'll do it when I > > get > > time. > > > > I track all this through the GitHub issues system. So if you want to > > enter > > the suggestion there please do it. Otherwise, I'll do it. > > > > Bruno > > --- > > > > Reply to this email directly or view it on GitHub: > > https://gist.github.com/2394695 > --- > > Reply to this email directly or view it on GitHub: > https://gist.github.com/2394695 --- Reply to this email directly or view it on GitHub: https://gist.github.com/2394695

Sure. My skype is offline most of the time but I'll turn it on. But that won't be before tomorrow as I'm travelling today.

Forgot. my skype id is bjouhier