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import gleam/dynamic
import gleam/int
import gleam/result
import gleam/string
import lustre
import lustre/attribute
import lustre/element.{type Element}
import lustre/event
// These examples are written with lustre_ui in mind. They'll work regardless,
// but to see what lustre_ui can do make sure to run each of these examples with
// the `--include-styles` flag:
//
// $ gleam run -m lustre/try -- --include-styles
//
// In your own apps, make sure to add the `lustre_ui` dependency and include the
// stylesheet somewhere.
import lustre/ui
import lustre/ui/aside
// MAIN ------------------------------------------------------------------------
pub fn main() {
let app = lustre.simple(init, update, view)
let assert Ok(_) = lustre.start(app, "#app", Nil)
}
// MODEL -----------------------------------------------------------------------
type Model {
Model(value: String, length: Int, max: Int)
}
fn init(_) -> Model {
Model(value: "", length: 0, max: 10)
}
// UPDATE ----------------------------------------------------------------------
pub opaque type Msg {
GotInput(value: String)
Reset
}
fn update(model: Model, msg: Msg) -> Model {
case msg {
GotInput(value) -> {
let length = string.length(value)
case length <= model.max {
True -> Model(..model, value: value, length: length)
False -> model
}
}
Reset -> Model(..model, value: "", length: 0)
}
}
// VIEW ------------------------------------------------------------------------
fn view(model: Model) -> Element(Msg) {
let styles = [#("width", "100vw"), #("height", "100vh"), #("padding", "1rem")]
let length = int.to_string(model.length)
let max = int.to_string(model.max)
let on_input = fn(event) {
use target <- result.try(dynamic.field("target", dynamic.dynamic)(event))
use value <- result.try(dynamic.field("value", dynamic.string)(target))
// Decoding the `value` from anevent target is so common we provider a decoder
// for it already:
//
// use value <- result.try(event.value(event))
Ok(GotInput(value))
}
ui.centre(
[attribute.style(styles)],
ui.aside(
[aside.content_first(), aside.align_centre()],
ui.field(
[],
[element.text("Write a message:")],
ui.input([attribute.value(model.value), event.on("input", on_input)]),
[element.text(length <> "/" <> max)],
),
ui.button([event.on_click(Reset)], [element.text("Reset")]),
),
)
}
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