[js] Module import support (#12384)

* [js] Module import support

* Generate aliases

* Allow `@:js.import(define)`

* add package.json

* move test

Author: RblSb

src-json/meta.json

@@ -561,6 +561,13 @@
 		"targets": ["TClass"],
 		"links": ["https://haxe.org/manual/target-javascript-require.html"]
 	},
+	{
+		"name": "JsImport",
+		"metadata": ":js.import",
+		"doc": "Generate ES module import statement for given extern. Produces import lines at the top of the generated JS output.",
+		"platforms": ["js"],
+		"targets": ["TClass"]
+	},
 	{
 		"name": "LuaRequire",
 		"metadata": ":luaRequire",

src/generators/genjs.ml

@@ -1666,6 +1666,71 @@ let generate js_gen com =
 
 	let ctx = alloc_ctx com es_version in
 	Gctx.map_source_header com.defines (fun s -> print ctx "// %s\n" s);
+
+	let import_statements = ref [] in
+	List.iter (fun mt -> match mt with
+		| TClassDecl c when (has_class_flag c CExtern) && Meta.has Meta.JsImport c.cl_meta && is_directly_used ctx.com c.cl_meta ->
+			let _, args, mp = Meta.get Meta.JsImport c.cl_meta in
+			let id = snd c.cl_path in
+			let flat_path = Path.flat_path (get_generated_class_path c) in
+			let alias = try
+				fst (Native.get_native_name c.cl_meta)
+			with Not_found ->
+				c.cl_meta <- (Meta.Native,[EConst (String(flat_path,SDoubleQuotes)),null_pos],null_pos) :: c.cl_meta;
+				Native.apply_native_paths mt;
+				flat_path
+			in
+			let err () =
+				abort ("Unsupported @:js.import format. Use:\n" ^
+				"	@:js.import('mylib.js')\n" ^
+				"	@:js.import('mylib.js', 'name')\n" ^
+				"	@:js.import(@default 'mylib.js')\n" ^
+				"	@:js.import(@star 'mylib.js')\n" ^
+				"'mylib.js' can also be replaced with mylibjs_path custom define,\nif you set it as -D mylibjs_path=\"mylib.js\"")
+				mp
+			in
+			let get_module_name expr =
+				match expr with
+					| EConst(String(module_name,_)),_ -> module_name
+					| EConst(Ident(define)),_ ->
+						begin try
+							let s = Define.raw_defined_value com.defines define in
+							Helper.unquote s
+						with Not_found ->
+							abort ("Define " ^ define ^ " with js library path is not specified") mp;
+						end
+					| _ -> err()
+			in
+			(match args with
+				(* @:js.import(@star "module") - namespace import *)
+				| [EMeta ((Meta.Custom "star",[],_),ename),_] ->
+					let module_name = get_module_name ename in
+					import_statements := (Printf.sprintf "import * as %s from \"%s\";" alias module_name) :: !import_statements
+				(* @:js.import(@default "module") - default import *)
+				| [EMeta ((Meta.Custom "default",[],_),ename),_] ->
+					let module_name = get_module_name ename in
+					import_statements := (Printf.sprintf "import %s from \"%s\";" alias module_name) :: !import_statements
+				(* @:js.import("module") - named import using class name *)
+				| [ename] ->
+					let module_name = get_module_name ename in
+					import_statements := (Printf.sprintf "import { %s as %s } from \"%s\";" id alias module_name) :: !import_statements
+				(* @:js.import("module", "exportName") - named import with alias *)
+				| [ename; (EConst(String(export_name,_)),_)] ->
+					let module_name = get_module_name ename in
+					import_statements := (Printf.sprintf "import { %s as %s } from \"%s\";" export_name alias module_name) :: !import_statements
+				| exprs ->
+					err ()
+			)
+		| _ -> ()
+	) com.types;
+	(match !import_statements with
+		| [] -> ()
+		| lines ->
+			List.iter (fun line ->
+				print ctx "%s\n" line
+			) (List.rev lines)
+	);
+
 	if has_feature ctx "Class" || has_feature ctx "Type.getClassName" then add_feature ctx "js.Boot.isClass";
 	if has_feature ctx "Enum" || has_feature ctx "Type.getEnumName" then add_feature ctx "js.Boot.isEnum";
 

tests/misc/js/projects/Issue10615/compile.hxml

@@ -0,0 +1,7 @@
+--main Main
+-dce full
+-D analyzer-optimize
+--class-path src
+--js bin/main.js
+--cmd node bin/main
+-D pixijs_path="../pixi.js"

tests/misc/js/projects/Issue10615/compile2.hxml

@@ -0,0 +1,8 @@
+--main Main
+-dce full
+-D analyzer-optimize
+--class-path src
+--js bin/main.js
+--cmd node bin/main
+-D js-es=6
+-D pixijs_path="../pixi.js"

tests/misc/js/projects/Issue10615/lib.js

@@ -0,0 +1,8 @@
+export const str = "str";
+export function increment(x) {
+    return x + 1;
+}
+
+export default function def() {
+    return "default function";
+}

tests/misc/js/projects/Issue10615/lib_default_class.js

@@ -0,0 +1,6 @@
+export default class Lib {
+    static def() {
+        return "default static";
+    }
+}
+

tests/misc/js/projects/Issue10615/lib_default_fun.js

@@ -0,0 +1,3 @@
+export default function def() {
+    return "default function";
+}

tests/misc/js/projects/Issue10615/multilib.js

@@ -0,0 +1,17 @@
+export class Foo {
+    static name() {
+        return "foo";
+    }
+}
+
+export class Bar {
+    static name() {
+        return "bar";
+    }
+}
+
+export default class DefClass {
+    name() {
+        return "default class";
+    }
+}

tests/misc/js/projects/Issue10615/package.json

@@ -0,0 +1,3 @@
+{
+  "type": "module"
+}

tests/misc/js/projects/Issue10615/pixi.js

@@ -0,0 +1,21 @@
+export class Application {
+	constructor(options) {}
+	test() {
+		return "test";
+	}
+	static name() {
+		return "Application";
+	}
+}
+
+export class Assets {
+	static load(url) {
+		return url;
+	}
+}
+
+export default class {
+	static name() {
+		return "default name";
+	}
+};