5 files changed, 142 insertions, 0 deletions
diff --git a/examples/06-custom-effects/README.md b/examples/06-custom-effects/README.md
new file mode 100644
index 0000000..283c81a
--- /dev/null
+++ b/examples/06-custom-effects/README.md
@@ -0,0 +1 @@
+# 06 Custom Effects
diff --git a/examples/06-custom-effects/gleam.toml b/examples/06-custom-effects/gleam.toml
new file mode 100644
index 0000000..b84e394
--- /dev/null
+++ b/examples/06-custom-effects/gleam.toml
@@ -0,0 +1,12 @@
+name = "app"
+version = "1.0.0"
+target = "javascript"
+
+[dependencies]
+gleam_stdlib = "~> 0.34 or ~> 1.0"
+lustre = { path = "../../" }
+lustre_ui = "~> 0.3"
+lustre_http = "~> 0.4"
+
+[dev-dependencies]
+gleeunit = "~> 1.0"
diff --git a/examples/06-custom-effects/manifest.toml b/examples/06-custom-effects/manifest.toml
new file mode 100644
index 0000000..fc33b28
--- /dev/null
+++ b/examples/06-custom-effects/manifest.toml
@@ -0,0 +1,26 @@
+# This file was generated by Gleam
+# You typically do not need to edit this file
+
+packages = [
+  { name = "argv", version = "1.0.1", build_tools = ["gleam"], requirements = [], otp_app = "argv", source = "hex", outer_checksum = "A6E9009E50BBE863EB37D963E4315398D41A3D87D0075480FC244125808F964A" },
+  { name = "gleam_community_ansi", version = "1.4.0", build_tools = ["gleam"], requirements = ["gleam_community_colour", "gleam_stdlib"], otp_app = "gleam_community_ansi", source = "hex", outer_checksum = "FE79E08BF97009729259B6357EC058315B6FBB916FAD1C2FF9355115FEB0D3A4" },
+  { name = "gleam_community_colour", version = "1.3.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_community_colour", source = "hex", outer_checksum = "A49A5E3AE8B637A5ACBA80ECB9B1AFE89FD3D5351FF6410A42B84F666D40D7D5" },
+  { name = "gleam_erlang", version = "0.24.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_erlang", source = "hex", outer_checksum = "26BDB52E61889F56A291CB34167315780EE4AA20961917314446542C90D1C1A0" },
+  { name = "gleam_json", version = "0.7.0", build_tools = ["gleam"], requirements = ["thoas", "gleam_stdlib"], otp_app = "gleam_json", source = "hex", outer_checksum = "CB405BD93A8828BCD870463DE29375E7B2D252D9D124C109E5B618AAC00B86FC" },
+  { name = "gleam_otp", version = "0.9.0", build_tools = ["gleam"], requirements = ["gleam_stdlib", "gleam_erlang"], otp_app = "gleam_otp", source = "hex", outer_checksum = "5FADBBEC5ECF3F8B6BE91101D432758503192AE2ADBAD5602158977341489F71" },
+  { name = "gleam_stdlib", version = "0.34.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "1FB8454D2991E9B4C0C804544D8A9AD0F6184725E20D63C3155F0AEB4230B016" },
+  { name = "gleeunit", version = "1.0.2", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "D364C87AFEB26BDB4FB8A5ABDE67D635DC9FA52D6AB68416044C35B096C6882D" },
+  { name = "glint", version = "0.14.0", build_tools = ["gleam"], requirements = ["gleam_stdlib", "gleam_community_colour", "gleam_community_ansi", "snag"], otp_app = "glint", source = "hex", outer_checksum = "21AB16D5A50D4EF34DF935915FDBEE06B2DAEDEE3FCC8584C6E635A866566B38" },
+  { name = "lustre", version = "3.1.3", build_tools = ["gleam"], requirements = ["argv", "gleam_community_ansi", "gleam_erlang", "gleam_json", "gleam_otp", "gleam_stdlib", "glint"], source = "local", path = "../.." },
+  { name = "lustre_http", version = "0.4.1", build_tools = ["gleam"], requirements = ["gleam_json", "lustre", "gleam_stdlib"], otp_app = "lustre_http", source = "hex", outer_checksum = "F2E575CA598D426DECD9F617500B4EDAF11BEEF4233B8D31D2D568219E5ACCED" },
+  { name = "lustre_ui", version = "0.3.0", build_tools = ["gleam"], requirements = ["gleam_stdlib", "gleam_community_colour", "lustre"], otp_app = "lustre_ui", source = "hex", outer_checksum = "F81BE5D20153CFFC717C2C4687A19375A8613528908AF7069DDA1B929C8398B1" },
+  { name = "snag", version = "0.3.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "snag", source = "hex", outer_checksum = "54D32E16E33655346AA3E66CBA7E191DE0A8793D2C05284E3EFB90AD2CE92BCC" },
+  { name = "thoas", version = "0.4.1", build_tools = ["rebar3"], requirements = [], otp_app = "thoas", source = "hex", outer_checksum = "4918D50026C073C4AB1388437132C77A6F6F7C8AC43C60C13758CC0ADCE2134E" },
+]
+
+[requirements]
+gleam_stdlib = { version = "~> 0.34 or ~> 1.0" }
+gleeunit = { version = "~> 1.0" }
+lustre = { path = "../../" }
+lustre_http = { version = "~> 0.4"}
+lustre_ui = { version = "~> 0.3" }
diff --git a/examples/06-custom-effects/src/app.ffi.mjs b/examples/06-custom-effects/src/app.ffi.mjs
new file mode 100644
index 0000000..c401b99
--- /dev/null
+++ b/examples/06-custom-effects/src/app.ffi.mjs
@@ -0,0 +1,11 @@
+import { Ok, Error } from "./gleam.mjs";
+
+export function read_localstorage(key) {
+  const value = window.localStorage.getItem(key);
+
+  return value ? new Ok(value) : new Error(undefined);
+}
+
+export function write_localstorage(key, value) {
+  window.localStorage.setItem(key, value);
+}
diff --git a/examples/06-custom-effects/src/app.gleam b/examples/06-custom-effects/src/app.gleam
new file mode 100644
index 0000000..289de5d
--- /dev/null
+++ b/examples/06-custom-effects/src/app.gleam
@@ -0,0 +1,92 @@
+import gleam/option.{type Option, None, Some}
+import lustre
+import lustre/attribute
+import lustre/effect.{type Effect}
+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
+
+// MAIN ------------------------------------------------------------------------
+
+pub fn main() {
+  let app = lustre.application(init, update, view)
+  let assert Ok(_) = lustre.start(app, "#app", Nil)
+}
+
+// MODEL -----------------------------------------------------------------------
+
+type Model {
+  Model(message: Option(String))
+}
+
+fn init(_) -> #(Model, Effect(Msg)) {
+  #(Model(message: None), read_localstorage("message", GotMessage))
+}
+
+// UPDATE ----------------------------------------------------------------------
+
+pub opaque type Msg {
+  GotInput(String)
+  GotMessage(Result(String, Nil))
+}
+
+fn update(model: Model, msg: Msg) -> #(Model, Effect(Msg)) {
+  case msg {
+    GotInput(input) -> #(
+      Model(message: Some(input)),
+      write_localstorage("message", input),
+    )
+    GotMessage(Ok(message)) -> #(Model(message: Some(message)), effect.none())
+    GotMessage(Error(_)) -> #(model, effect.none())
+  }
+}
+
+fn read_localstorage(
+  key: String,
+  to_msg: fn(Result(String, Nil)) -> msg,
+) -> Effect(msg) {
+  effect.from(fn(dispatch) {
+    do_read_localstorage(key)
+    |> to_msg
+    |> dispatch
+  })
+}
+
+@external(javascript, "./app.ffi.mjs", "read_localstorage")
+fn do_read_localstorage(_key: String) -> Result(String, Nil) {
+  Error(Nil)
+}
+
+fn write_localstorage(key: String, value: String) -> Effect(msg) {
+  effect.from(fn(_) { do_write_localstorage(key, value) })
+}
+
+@external(javascript, "./app.ffi.mjs", "write_localstorage")
+fn do_write_localstorage(_key: String, _value: String) -> Nil {
+  Nil
+}
+
+// VIEW ------------------------------------------------------------------------
+
+fn view(model: Model) -> Element(Msg) {
+  let styles = [#("width", "100vw"), #("height", "100vh")]
+  let message = option.unwrap(model.message, "")
+
+  ui.centre(
+    [attribute.style(styles)],
+    ui.field(
+      [],
+      [],
+      ui.input([attribute.value(message), event.on_input(GotInput)]),
+      [element.text("Type a message and refresh the page")],
+    ),
+  )
+}