I'm not convinced. I'm not familiar with the last approach but it seems to me that with a couple of higher-order functions in JavaScript, the code will quickly

I'm not convinced. I'm not familiar with the last approach but it seems to me that with a couple of higher-order functions in JavaScript, the code will quickly become more manageable. function getPhoto(tag, handlerCallback) { asyncChain(requestTag, requestOneFrom)(tag, function(photoSizes) { handlerCallback(sizesToPhoto(photoSizes)); }); } getPhoto('tokyo', drawOnScreen);