Elm ID

Why?

Different resources may have different representation for an ID (such as String or Int), but two very different resources may also both use a single representation.

This package provides an Id type that leverages the type system to reference your resources in the most type-safe way imaginable.

Example

Imagine an application that handles three types of resources: users, articles and comments. Users are referenced by string-based IDs and both articles and comments are referenced by integer-based IDs. However, using the raw Int type to identify articles and comments would be a major foot-gun as an ID of 5 might represent an article or a comment and there is nothing you can do to prevent developers to misuse an article ID to reference a comment.

With this package, the solution becomes quite simple and elegant:

type User =
    User
        { id : UserID
        , name : String
        }


type Article =
    Article
        { id : ArticleID
        , title : String
        , comments : List Comment
        }


type Comment =
    Comment
        { id : CommentID
        , content : String
        }


type alias UserID =
    Id String User


type alias ArticleID =
    Id Int Article


type alias CommentID =
    Id Int Comment

Licence

BSD-3-Clause © Hugo Saracino