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Create HTML templates, single page applications, Web Components, and real-time server components in Gleam!
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src/lustre/event.gleam
//// To read the full documentation for this module, please visit
//// [https://pkg.hayleigh.dev/lustre/api/lustre/event](https://pkg.hayleigh.dev/lustre/api/lustre/event)
// IMPORTS ---------------------------------------------------------------------
import gleam/dynamic.{DecodeError, Dynamic}
import gleam/result
import lustre/attribute.{Attribute}
import lustre/effect.{Effect}
// TYPES -----------------------------------------------------------------------
type Decoded(a) =
Result(a, List(DecodeError))
// EFFECTS ---------------------------------------------------------------------
@target(javascript)
///
@external(javascript, "../lustre.ffi.mjs", "emit")
pub fn emit(event: String, data: any) -> Effect(msg)
// CUSTOM EVENTS ---------------------------------------------------------------
///
pub fn on(
name: String,
handler: fn(Dynamic) -> Result(msg, error),
) -> Attribute(msg) {
attribute.on(name, handler)
}
// MOUSE EVENTS ----------------------------------------------------------------
///
pub fn on_click(msg: msg) -> Attribute(msg) {
use _ <- on("click")
Ok(msg)
}
///
pub fn on_mouse_down(msg: msg) -> Attribute(msg) {
use _ <- on("mousedown")
Ok(msg)
}
///
pub fn on_mouse_up(msg: msg) -> Attribute(msg) {
use _ <- on("mouseup")
Ok(msg)
}
///
pub fn on_mouse_enter(msg: msg) -> Attribute(msg) {
use _ <- on("mouseenter")
Ok(msg)
}
///
pub fn on_mouse_leave(msg: msg) -> Attribute(msg) {
use _ <- on("mouseleave")
Ok(msg)
}
///
pub fn on_mouse_over(msg: msg) -> Attribute(msg) {
use _ <- on("mouseover")
Ok(msg)
}
///
pub fn on_mouse_out(msg: msg) -> Attribute(msg) {
use _ <- on("mouseout")
Ok(msg)
}
// KEYBOARD EVENTS -------------------------------------------------------------
/// Listens for key presses on an element, and dispatches a message with the
/// current key being pressed.
///
pub fn on_keypress(msg: fn(String) -> msg) -> Attribute(msg) {
use event <- on("keypress")
event
|> dynamic.field("key", dynamic.string)
|> result.map(msg)
}
/// Listens for key dow events on an element, and dispatches a message with the
/// current key being pressed.
///
pub fn on_keydown(msg: fn(String) -> msg) -> Attribute(msg) {
use event <- on("keydown")
event
|> dynamic.field("key", dynamic.string)
|> result.map(msg)
}
/// Listens for key up events on an element, and dispatches a message with the
/// current key being released.
///
pub fn on_keyup(msg: fn(String) -> msg) -> Attribute(msg) {
use event <- on("keyup")
event
|> dynamic.field("key", dynamic.string)
|> result.map(msg)
}
// FORM EVENTS -----------------------------------------------------------------
///
pub fn on_input(msg: fn(String) -> msg) -> Attribute(msg) {
use event <- on("input")
value(event)
|> result.map(msg)
}
pub fn on_check(msg: fn(Bool) -> msg) -> Attribute(msg) {
use event <- on("change")
checked(event)
|> result.map(msg)
}
pub fn on_submit(msg: msg) -> Attribute(msg) {
use event <- on("submit")
let _ = prevent_default(event)
Ok(msg)
}
// FOCUS EVENTS ----------------------------------------------------------------
pub fn on_focus(msg: msg) -> Attribute(msg) {
use _ <- on("focus")
Ok(msg)
}
pub fn on_blur(msg: msg) -> Attribute(msg) {
use _ <- on("blur")
Ok(msg)
}
// DECODERS --------------------------------------------------------------------
///
pub fn value(event: Dynamic) -> Decoded(String) {
event
|> dynamic.field("target", dynamic.field("value", dynamic.string))
}
///
pub fn checked(event: Dynamic) -> Decoded(Bool) {
event
|> dynamic.field("target", dynamic.field("checked", dynamic.bool))
}
///
pub fn mouse_position(event: Dynamic) -> Decoded(#(Float, Float)) {
use x <- result.then(dynamic.field("clientX", dynamic.float)(event))
use y <- result.then(dynamic.field("clientY", dynamic.float)(event))
Ok(#(x, y))
}
// UTILS -----------------------------------------------------------------------
@external(javascript, "../lustre.ffi.mjs", "prevent_default")
pub fn prevent_default(event: Dynamic) -> Nil {
Nil
}
@external(javascript, "../lustre.ffi.mjs", "stop_propagation")
pub fn stop_propagation(event: Dynamic) -> Nil {
Nil
}