[quinnirill]

With Trine this would be

    function process () {
      return this
        ::filter(isOk)
        ::map(toOtherType)
        ::flatten();
    }

and then later:

    groupsOfItems::map(process);

Granted, the `flatten` function is not in the Trine yet, somehow forgot that from the initial release.

[CrossEye]

Ok, that helps make it a bit more palatable to me.

Thanks for the information.

One question, though: How do user functions interact in here? If you didn't include `flatten`, but I had my own version of it, would it be straightforward for me to build `process` using my own `flatten`? Do I have to modify some Trine objects, or can I use some simple function references?

Obviously I haven't yet actually dug into the Trine code. Perhaps this weekend.

[quinnirill]

Happy to help!

Yes, you can use just simple function references, e.g. you could just define flatten as so

    function * flatten () {
      for ( const item of this ) {
        yield * item;
      }
    }

And it would work just like it was part of Trine - in fact that's probably how it's going to be implemented in Trine. The chaining is not a feature of Trine, but the function bind syntax proposal ( https://github.com/zenparsing/es-function-bind ), Trine has merely been designed to work well with this syntax.