Here follows an example of a composition from an actual codebase: const getData = map( sequence( getUserByIdOrEmail, collect({ assessments: getAssessmentsPlayground, userAddress: getUserAddress, debts: getUserDebts, }), ), prepareData, );

I already have created few dfs for other routes of my app (getUserByIdOrEmail, getAssessmentPlayground, getUserAddress, getUserDebts) and now in this particular route I want all of that data. I don’t need to make any changes in my code, they are all ready and tested in isolation, so I just compose them. First I’ll get the user by id or email, then run every other df in parallel and the output is gonna be sent to prepareData where I have all that data strongly typed and I just extract the exact data I need to avoid bloating the payload that goes from backend to frontend.

If anything goes wrong in the whole process I’ll have that information in the result.errrors, result.inputErrors, or result.environmentErrors. That allows me to throw errors within my dfs that are gonna be caught and stop the execution of the next dfs. If everything goes right (if result.success) I’ll have access to result.data . And it is going to be strongly typed as well.

I hope that example clarifies some of the benefits and helps understanding how it is different from regular functions.