I find the JavaScript code not very useful for human input, if the intended audience is not restricted to web developers (a code like interface might still be a

I find the JavaScript code not very useful for human input, if the intended audience is not restricted to web developers (a code like interface might still be a good idea). If your intended offering is for devs it would neat some more advanced features to be useful. More interesting is the question whether you want to support joins. If you do not then you are restricted to concatenation (either in length or in width). Another question is do you want to allow filtering too? If you want joins i would recommend writing a small query planner because there are some hugely performant optimisations with joins (and filters). If you restrict the possible calculations across loops to simple things like sums, max one could parallelize it between workers with some workm An interesting avenue for small scale monetisation would be to allow paying users to run them "in the cloud" in JavaScript edge VMs (not sure how they are called exactly cloudflare and others have them). One premium feature could be to pick one of multiple locations where to start them between closest to the data sources or closest data consumer based on the expected ratio of input/output. For large local files and poor connections client side calculations could be used automatically.