test: add integration test for TypeScript declarations

.github/workflows/ci.yaml

@@ -470,6 +470,10 @@ jobs:
         run: make
         working-directory: ./test/javascript_prelude
 
+      - name: Test generated TypeScript declarations
+        run: make test
+        working-directory: ./test/typescript_declarations
+
       - name: Test export of hex tarball
         run: make test
         working-directory: ./test/hextarball

Makefile

@@ -24,6 +24,7 @@ test: ## Run the compiler unit tests
 	cd test/project_javascript && cargo run clean && cargo run check && cargo run test
 	cd test/project_deno && cargo run clean && cargo run check && cargo run test
 	cd test/hextarball && make test
+	cd test/typescript_declarations && make test
 	cd test/running_modules && make test
 	cd test/subdir_ffi && make
 
@@ -51,6 +52,10 @@ test-watch: ## Run compiler tests when files change
 export-hex-tarball-test: ## Run `gleam export hex-tarball` and verify it is created
 	cd test/hextarball && make test
 
+.PHONY: typescript-declarations-test
+typescript-declarations-test: ## Check that generated TypeScript declaration compile
+	cd test/typescript_declarations && make test
+
 .PHONY: benchmark
 benchmark: ## Run the benchmarks
 	cd benchmark/list && make

test/typescript_declarations/.gitignore

@@ -0,0 +1,4 @@
+*.beam
+*.ez
+/build
+erl_crash.dump

test/typescript_declarations/Makefile

@@ -0,0 +1,8 @@
+.PHONY: clean
+clean:
+	rm -rf build
+
+.PHONY: test
+test:
+	cargo run --quiet -- build
+	tsc ./main.ts --strict --noEmit --lib es2015,dom

test/typescript_declarations/README.md

@@ -0,0 +1,3 @@
+# typescript_declarations
+
+Check that generated TypeScript declarartions are correct. This requires `tsc` installed and be in PATH.

test/typescript_declarations/gleam.toml

@@ -0,0 +1,9 @@
+name = "typescript_declarations"
+version = "1.0.0"
+target = "javascript"
+
+[javascript]
+typescript_declarations = true
+
+[dependencies]
+gleam_stdlib = ">= 0.44.0 and < 2.0.0"

test/typescript_declarations/main.ts

@@ -0,0 +1,79 @@
+import type { Option$ } from "./build/dev/javascript/gleam_stdlib/gleam/option.d.mts";
+import { List, Ok, Result } from "./build/dev/javascript/typescript_declarations/gleam.mjs";
+import * as Gleam from "./build/dev/javascript/typescript_declarations/typescript_declarations.mjs"
+
+// Check add and add_alias
+const sum: number = Gleam.add_alias(Gleam.add(1, 2), 908);
+
+// Check ID lists constants
+const count_of_moderators: number = Gleam.moders.countLength();
+const count_of_administrators: number = Gleam.admins.countLength();
+
+// Check add_one closure
+const add_one: (_: number) => number = Gleam.add_one()
+const two: number = add_one(1)
+
+// Check UserId type alias
+const first_moderator: Gleam.UserId = Gleam.moders.toArray()[ 0];
+const first_moderator_num: number = first_moderator;
+const me: UserID = 84738;
+type UserID = Gleam.UserId;
+
+// Check is_divisible_by
+const is_five_divisible_by_two: boolean = Gleam.is_divisible_by(5, 2);
+
+// Check extern alert function if we are in browser target
+if (typeof window != undefined) {
+  Gleam.js_alert("Hello!");
+}
+
+// Check generic twice function
+const twice_number: number = Gleam.twice(45, add_one);
+
+// Check recursive sum_list
+const sum_of_list: number = Gleam.sum_list(List.fromArray([10, 25, 65383, 8910, 1893]), 0);
+
+// Check results
+const result_ok: Result<number, number> = new Ok(10);
+const is_ok: boolean = Gleam.is_ok_result(result_ok);
+
+// Check name_description tuple
+const name: string = Gleam.name_description[0];
+const description: string = Gleam.name_description[1];
+
+// Check User and related functions
+const user: Gleam.User$ = new Gleam.User("King", 83874, new Gleam.PlainUser());
+const guest: Gleam.User$ = new Gleam.Guest();
+const user_username: Option$<string> = Gleam.user_name(user);
+const guest_username: Option$<string> = Gleam.user_name(guest);
+const plain_user_string: string = Gleam.role_string((user as Gleam.User).role);
+
+// Check Either type
+const left_either: Gleam.Either$<string, number> = new Gleam.Left("Hello!");
+const right_either: Gleam.Either$<string, number> = new Gleam.Right(3747);
+
+// This added since TypeScript will give warnings about unused things otherwise
+void [
+  sum,
+  count_of_administrators,
+  count_of_moderators,
+  add_one,
+  two,
+  first_moderator,
+  first_moderator_num,
+  me,
+  is_five_divisible_by_two,
+  twice_number,
+  sum_of_list,
+  result_ok,
+  is_ok,
+  name,
+  description,
+  user,
+  guest,
+  user_username,
+  guest_username,
+  plain_user_string,
+  left_either,
+  right_either,
+]

test/typescript_declarations/manifest.toml

@@ -0,0 +1,9 @@
+# This file was generated by Gleam
+# You typically do not need to edit this file
+
+packages = [
+  { name = "gleam_stdlib", version = "0.62.1", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "0080706D3A5A9A36C40C68481D1D231D243AF602E6D2A2BE67BA8F8F4DFF45EC" },
+]
+
+[requirements]
+gleam_stdlib = { version = ">= 0.44.0 and < 2.0.0" }

test/typescript_declarations/src/typescript_declarations.gleam

@@ -0,0 +1,102 @@
+import gleam/option.{type Option}
+import gleam/result
+
+/// Greeting for user
+pub const greeting: String = "Hello, dear user!"
+
+/// Add two numbers
+pub fn add(first a: Int, second b: Int) -> Int {
+  a + b
+}
+
+/// Returns true if number is divisible by another
+pub fn is_divisible_by(number num: Int, divider div: Int) -> Bool {
+  case num % div {
+    0 -> True
+    _ -> False
+  }
+}
+
+/// ID of specific user
+pub type UserId =
+  Int
+
+/// Alias to add function
+pub const add_alias = add
+
+/// Return function that will add one to given number
+pub fn add_one() -> fn(Int) -> Int {
+  let func = add(1, _)
+  func
+}
+
+/// IDs of administrators
+pub const admins: List(UserId) = [00_010, 00_000, 00_001, 00_002, 29_373]
+
+/// IDs of moderators
+pub const moders = [01_013, 36_371, 74_839, 18_930, 36_373]
+
+/// Create alert on browser target
+@external(javascript, "globalThis", "alert")
+pub fn js_alert(text: String) -> Nil
+
+/// Twice value via given function
+pub fn twice(val: a, function: fn(a) -> a) -> a {
+  function(function(val))
+}
+
+/// Recursively sum list of numbers
+pub fn sum_list(list: List(Int), total: Int) -> Int {
+  case list {
+    [first, ..rest] -> sum_list(rest, total + first)
+    [] -> total
+  }
+}
+
+/// Returns true if result is ok
+pub fn is_ok_result(res: Result(a, b)) -> Bool {
+  result.is_ok(res)
+}
+
+/// First value is name and second is description
+pub const name_description = #("MyApp", "My Awesome Application")
+
+/// Role of user
+pub type UserRole {
+  /// Administrator
+  Administrator
+  /// Moderator
+  Moderator
+  /// Just a user
+  PlainUser
+}
+
+/// Represents user
+pub type User {
+  /// Represents registered user
+  User(username: String, id: UserId, role: UserRole)
+  /// Represents guest without any data
+  Guest
+}
+
+/// Get name of user, None if user is guest
+pub fn user_name(user: User) -> Option(String) {
+  case user {
+    User(name, ..) -> option.Some(name)
+    Guest -> option.None
+  }
+}
+
+/// Format user role as string
+pub fn role_string(role: UserRole) -> String {
+  case role {
+    PlainUser -> "user"
+    Moderator -> "moderator"
+    Administrator -> "admin"
+  }
+}
+
+pub type Either(a, b) {
+  Left(a)
+  Right(b)
+}