Posts

Bang! And Other Infix Functions

Published July 25, 2016 · 4 Minute Read · ∞ Permalink

Elm is usually pretty clear, but there are certain things that are a little hard to search for. One of those is the ! operator, introduced in 0.17. What does it do? Where does it come from? And even more important, when should you use it?

Duplicating Scientists in Elm: Stop Sharing State

Published July 11, 2016 · 6 Minute Read · ∞ Permalink

When you’re building an app with Elm, you’ll find a common problem: where do you put shared state in models? Let’s take selecting an item for viewing as an example. You’ll start out having a model field with a selected item and one with a collection. But that’s duplication! How do you keep the model state in sync when one side has to change?

Duplicate, Message, or Update? Contexts in Elm Components

Published July 5, 2016 · 4 Minute Read · ∞ Permalink

Imagine: you’re implementing your Elm app. It’s getting bigger all the time, and you’re happy that it’s growing. Hooray! But now you need to make HTTP requests… from a child component. What to do? You don’t want to duplicate the HTTP config as a field on the user everywhere, right? But likewise, you don’t want to forward actions to the parent just to make HTTP requests, right? What’s the way to solve this while sticking with the best architecture for your app?

Candy and Allowances, Part II: Child-Child Communication in Elm

Published June 27, 2016 · 7 Minute Read · ∞ Permalink

UPDATE 2017-01-16: before you read this, read the reuse section of the Elm guide. It will set you up in a better way! The text below is preserved for reference purposes.

In our previous article we talked about how parents and children can communicate with one another in Elm. But how about when you need two child components to know about each others state? Hmm…

Candy and Allowances: Parent-Child Communication in Elm

Published June 23, 2016 · 9 Minute Read · ∞ Permalink

UPDATE 2017-01-16: before you read this, read the reuse section of the Elm guide. It will set you up in a better way! The text below is preserved for reference purposes.

Nobody wants to feel like their application holds together by duct tape and baling wire. Coupling components is icky, but… sometimes you’ve got a parent and child components that just have to talk to each other. It can feel like you’re missing something simple when these situations come up. Do you have to give up on clean separation of concerns just to get it working? There’s hope, though: this problem is not as difficult as it seems on the surface.