The author talks about Immutable.js, but doesn't mention Records, which have been a real godsend in my application. I use Immutable.Record with types [1] (using

The author talks about Immutable.js, but doesn't mention Records, which have been a real godsend in my application. I use Immutable.Record with types [1] (using Flow), and I feel very confident with this setup. You are forced to set default values for every key, and the code will crash if you try to set a key that hasn't been defined. It's really great to have typed Records (often nested), and I expose the getters as regular properties so that I don't have to call "get()" all the time. I agree that it's not perfect, but it's miles ahead of anything I've worked with in the past (at least in terms of JavaScript.) JSON schemas are awesome, and I like the idea of validating types at runtime on the front-end. I already have a JSON schema that defines my API (I use Swagger), so I could even go one step further and auto-generate my typed Records directly from the schema. I'll get immediate feedback about any type errors in my JS codebase as soon as I make changes to the API. I generate my Swagger API specification automatically from some RSpec tests (using rswag [2]), and I also run Flow during CI, so this would result in a broken build. I could also make this work with the data I'm inlining in the HTML to hydrate the Redux store. Random aside: I also have a one set of data that just gets dumped into a jsonb database column, so the schema for this specific data is only being defined by the front-end code. In my backend I'm always careful to provide a default value, but it's not really critical data. Anyway, I just realized that I should be defining this jsonb column as an actual model, but instead of ActiveRecord, I could use ActiveModel and a plain Ruby class. That's a neat idea. It would give me a schema and validations on the backend, while still having the flexibility and performance of storing everything in a single json column. [1] https://gist.github.com/glenjamin/75a96b45f4bb5c6ac221815d28c548dd https://gist.github.com/glenjamin/75a96b45f4bb5c6ac221815d28... [2] https://github.com/domaindrivendev/rswag https://github.com/domaindrivendev/rswag