v.gen.js: Interfaces support, fix for error propagation & panic stacktraces (#11471)

vlib/builtin/js/builtin.js.v

@@ -79,3 +79,12 @@ pub fn (r rune) str() string {
 
 	return sb.str()
 }
+
+fn js_stacktrace() string {
+	stacktrace := ''
+	#let err = new TypeError();
+	#err.name = 'stacktrace: '
+	#stacktrace.str = err.stack
+
+	return stacktrace
+}

vlib/builtin/js/builtin.v

@@ -7,7 +7,7 @@ module builtin
 fn (a any) toString()
 
 pub fn panic(s string) {
-	eprintln('V panic: $s')
+	eprintln('V panic: $s\n$js_stacktrace()')
 	exit(1)
 }
 

vlib/v/gen/js/fn.v

@@ -130,9 +130,16 @@ fn (mut g JsGen) method_call(node ast.CallExpr) {
 	}
 
 	if typ_sym.kind == .interface_ && (typ_sym.info as ast.Interface).defines_method(node.name) {
-		// g.write('${g.js_name(receiver_type_name)}_name_table')
-		// g.expr(node.left)
-		g.writeln('/* TODO: Interface call */')
+		g.expr(it.left)
+		g.gen_deref_ptr(it.left_type)
+		g.write('.${it.name}(')
+		for i, arg in it.args {
+			g.expr(arg.expr)
+			if i != it.args.len - 1 {
+				g.write(', ')
+			}
+		}
+		g.write(')')
 		return
 	}
 
@@ -229,9 +236,9 @@ fn (mut g JsGen) method_call(node ast.CallExpr) {
 			.propagate {
 				panicstr := '`optional not set (\${err})`'
 				if g.file.mod.name == 'main' && g.fn_decl.name == 'main.main' {
-					g.writeln('return builtin.panic($panicstr)')
+					g.writeln('return panic($panicstr)')
 				} else {
-					g.writeln('builtin.js_throw(err)')
+					g.writeln('js_throw(err)')
 				}
 			}
 			else {}
@@ -315,7 +322,7 @@ fn (mut g JsGen) gen_call_expr(it ast.CallExpr) {
 				g.stmt(it.or_block.stmts.last())
 			}
 			.propagate {
-				panicstr := '`optional not set (\${err})`'
+				panicstr := '`optional not set (\${err.val.msg})`'
 				if g.file.mod.name == 'main' && g.fn_decl.name == 'main.main' {
 					g.writeln('return panic($panicstr)')
 				} else {

vlib/v/gen/js/js.v

@@ -156,6 +156,45 @@ pub fn gen(files []&ast.File, table &ast.Table, pref &pref.Preferences) string {
 	if g.pref.is_test {
 		g.gen_js_main_for_tests()
 	}
+	g.enter_namespace('main')
+	// generate JS methods for interface methods
+	for _, iface_types in g.table.iface_types {
+		for ty in iface_types {
+			sym := g.table.get_type_symbol(ty)
+			for method in sym.methods {
+				p_sym := g.table.get_type_symbol(method.params[0].typ)
+				mname := g.js_name(p_sym.name) + '_' + method.name
+				g.write('${g.js_name(sym.name)}.prototype.$method.name = function(')
+				for i, param in method.params {
+					if i == 0 {
+						continue
+					}
+					g.write('${g.js_name(param.name)}')
+					if i != method.params.len - 1 {
+						g.write(',')
+					}
+				}
+				g.writeln(') {')
+				g.inc_indent()
+				g.write('return ${mname}(')
+				for i, param in method.params {
+					if i == 0 {
+						g.write('this')
+					} else {
+						g.write('${g.js_name(param.name)}')
+					}
+					if i != method.params.len - 1 {
+						g.write(',')
+					}
+				}
+				g.writeln(')')
+				g.dec_indent()
+				g.writeln('}')
+			}
+		}
+	}
+	g.write('js_main();')
+	g.escape_namespace()
 	// resolve imports
 	deps_resolved := graph.resolve()
 	nodes := deps_resolved.nodes
@@ -178,6 +217,7 @@ pub fn gen(files []&ast.File, table &ast.Table, pref &pref.Preferences) string {
 	out += g.out.str()
 
 	/*
+	TODO(playX): Again add support for these doc comments
 	for node in nodes {
 		name := g.js_name(node.name).replace('.', '_')
 		if g.enable_doc {
@@ -212,6 +252,7 @@ pub fn gen(files []&ast.File, table &ast.Table, pref &pref.Preferences) string {
 		// public scope
 		out += '\n'
 	}*/
+
 	if g.pref.sourcemap {
 		out += g.create_sourcemap()
 	}
@@ -229,7 +270,7 @@ fn (g JsGen) create_sourcemap() string {
 
 pub fn (mut g JsGen) gen_js_main_for_tests() {
 	g.enter_namespace('main')
-	g.writeln('(function() {  ')
+	g.writeln('function js_main() {  ')
 	g.inc_indent()
 	all_tfuncs := g.get_all_test_function_names()
 
@@ -256,7 +297,7 @@ pub fn (mut g JsGen) gen_js_main_for_tests() {
 		g.writeln('bt.end_testing();')
 	}
 	g.dec_indent()
-	g.writeln('})();')
+	g.writeln('}')
 	g.escape_namespace()
 }
 
@@ -888,9 +929,13 @@ fn (mut g JsGen) expr(node ast.Expr) {
 				if node.op == .amp {
 					// if !node.right_type.is_pointer() {
 					// kind of weird way to handle references but it allows us to access type methods easily.
+					/*
 					g.write('(function(x) {')
 					g.write(' return { val: x, __proto__: Object.getPrototypeOf(x), valueOf: function() { return this.val; } }})(  ')
 					g.expr(node.right)
+					g.write(')')*/
+					g.write('new \$ref(')
+					g.expr(node.right)
 					g.write(')')
 					//} else {
 					//		g.expr(node.right)
@@ -1406,11 +1451,11 @@ fn (mut g JsGen) gen_method_decl(it ast.FnDecl, typ FnGenType) {
 		// there is no concept of main in JS but we do have iife
 		g.writeln('/* program entry point */')
 
-		g.write('(')
+		// g.write('(')
 		if has_go {
 			g.write('async ')
 		}
-		g.write('function(')
+		g.write('function js_main(')
 	} else if it.is_anon {
 		g.write('function (')
 	} else {
@@ -1451,9 +1496,18 @@ fn (mut g JsGen) gen_method_decl(it ast.FnDecl, typ FnGenType) {
 	g.writeln('}')
 
 	if is_main {
-		g.write(')();')
+		// g.write(')')
 	}
 	g.writeln('')
+
+	for attr in it.attrs {
+		match attr.name {
+			'export' {
+				g.writeln('globalThis.$attr.arg = ${g.js_name(it.name)};')
+			}
+			else {}
+		}
+	}
 	/*
 	if typ == .alias_method || typ == .iface_method {
 		sym := g.table.get_final_type_symbol(it.params[0].typ.set_nr_muls(0))
@@ -1733,7 +1787,7 @@ fn (mut g JsGen) gen_return_stmt(it ast.Return) {
 	fn_return_is_optional := g.fn_decl.return_type.has_flag(.optional)
 	if node.exprs.len == 0 {
 		if fn_return_is_optional {
-			g.writeln('return {}')
+			g.writeln('return {state: new int(0)}')
 		} else {
 			g.writeln('return;')
 		}