Programming Elm

Use Extensible Records

Now that you’ve organized the salad state, you need to handle the contact-related state. You’ve seen the pitfalls of nested state. In this section, you will learn a different approach by using extensible records to create a Contact type without nesting state. Yet, you will still build a separate updateContact function that only changes contact-related fields.

Extract the Contact

You need to make a Contact type alias, but it will differ from the type aliases you’ve made previously. Below the Salad type alias, add this code:

larger/examples/SaladBuilder04.elm

type alias Contact c =
    { c
        | name : String
        , email : String
        , phone : String
    }

This is an extensible record type. An extensible record resembles ...