Reference: https://github.com/fantasyland/fantasy-land
One aspect to consider is that most JS programmers aren't familiar with the fantasy-land interface. This can be good, so there is a more noticeable difference between Promises and Readers.
However, many people is familiar with for example Bluebird. In bluebird, the .map() method does apply a function to each element of the resolved array, conflicting with the .map definition for functors in the fantasy-land spec.
Also, fantasy-land seems a bit inconvenient, compared to the Promises-like interface, in that you have to explicitly return a reader from .chain, where .then will wrap the value for you if necessary. So only fantasy-land compatible interface doesn't sound a great option.
Reference: https://github.com/fantasyland/fantasy-land
One aspect to consider is that most JS programmers aren't familiar with the fantasy-land interface. This can be good, so there is a more noticeable difference between Promises and Readers.
However, many people is familiar with for example Bluebird. In bluebird, the
.map()method does apply a function to each element of the resolved array, conflicting with the.mapdefinition for functors in the fantasy-land spec.Also, fantasy-land seems a bit inconvenient, compared to the Promises-like interface, in that you have to explicitly return a reader from
.chain, where.thenwill wrap the value for you if necessary. So onlyfantasy-landcompatible interface doesn't sound a great option.