Sketch Lustre Experimental

In case you’re here and don’t know Sketch, take a look at sketch package!

Setup

If you’re here, it means you’re ready to test the future of Sketch Lustre! Be careful, unexpected things can happen. sketch_lustre_experimental exposes one entrypoint, sketch/lustre/experimental, containing everything needed to get started.

// main.gleam
import lustre
import sketch
import sketch/lustre/experimental as sketch_lustre

pub fn main() {
  // Initialise the cache. Two strategies can be used. Ephemeral caches are designed as throw-away caches.
  let assert Ok(_) = sketch.stylesheet(strategy: sketch.Ephemeral)
  // Generate the partial view function, compatible with Lustre's runtime.
  lustre.simple(init, update, view)
  // And voilà!
  |> lustre.start("#app", Nil)
}

fn view(model) {
  // Add the sketch CSS generation "view middleware".
  use <- sketch_lustre.render(in: [sketch_lustre.node()])
  // Run your actual view function.
  my_view(model)
}

Usage

sketch_lustre_experimental exposes two modules to help you build your site, similarly to Lustre: sketch/lustre/experimental/element and sketch/lustre/experimental/element/html. The first one let you use raw element generation and exposes the Lustre Element(msg) type. Every time you need elements helpers, i.e. element, fragment, or even keyed, use directly lustre/element module.

NB: all elements can be generated using the correct function, or using its “underscored” version. In the second case, Sketch Lustre behaves exactly like Lustre, and will not add another class. This is helpful when you want to use a simple node, without any class linked on it.

import sketch/css
import sketch/css/length.{px}
import sketch/lustre/experimental/element
import sketch/lustre/experimental/element/html

fn main_style() {
  css.class([
    css.background("red"),
    css.font_size(px(16)),
  ])
}

fn view(model: Int) {
  html.div(main_style(), [], [
    html.div_([], [
      html.text(int.to_string(model)),
    ]),
  ])
}

And you’re done! Enjoy your Lustre app, Sketch-enhanced!

Final notes

On Sketch Lustre Experimental Element

A Sketch Element(msg) is a Lustre Element(msg), with class name directly linked on it. You don’t need anything to do to get a lustre/element.Element(msg). This also means you can use any Lustre Element(msg) function you already have.

Usage with Shadow DOM

In browser, Sketch can work with a Shadow DOM, in order to hide the compiled styles from the rest of the application. With a proper shadow root (represented as a Dynamic in Gleam), you can use sketch/lustre/experimental.shadow() to render a stylesheet in the shadow root directly. In the same way you can initialize the cache to render in document or in a style node, you can use a shadow root to paint styles in your application!