You need to explain more - for example what do you mean by a "partial"? A quick search for "partial functions" gave me several links to mathematics articles. When I followed the links to the composition modules I got more of the same impenetrable context-less style.<p>What I did get from the article is something that works a lot like promises:<p>- async functions return type of "eventual" data (in your case, a function you pass a callback to)<p>- various other functions that can operate on that eventual data type to return more eventual data<p>What does this style offer that standard promises doesn't?