diff --git a/vlib/builtin/js/map.js.v b/vlib/builtin/js/map.js.v
index 94a88a5e0e..eec4815f46 100644
--- a/vlib/builtin/js/map.js.v
+++ b/vlib/builtin/js/map.js.v
@@ -10,7 +10,7 @@ fn (mut m map) internal_set(key JS.Any, val JS.Any) {
 	//$if es5 {
 	#if (key.hasOwnProperty('$toJS')) key = key.$toJS();
 	#if (!(key in m.val.map)) m.val.length++;
-	#m.val.map[key] = val
+	#m.val.map[key].val = val
 	/*} $else {
 		# if (key.hasOwnProperty('$toJS')) key = key.$toJS();
 		# m.val.m.set(key,val);
@@ -23,7 +23,7 @@ fn (mut m map) internal_get(key JS.Any) JS.Any {
 	mut val := JS.Any(unsafe { nil })
 	//$if es5 {
 	#if (typeof key != "string" && key.hasOwnProperty('$toJS')) key = key.$toJS();
-	#val =  m.val.map[key]
+	#val =  m.val.map[key].val
 	/*} $else {
 		# if (key.hasOwnProperty('$toJS')) key = key.$toJS();
 		# val = m.val.m.get(key)
@@ -49,14 +49,14 @@ pub fn (m &map) free() {}
 
 pub fn (m map) keys() array {
 	ret := JS.makeEmptyArray()
-	#for (var key in m.map) array_push(ret,new string(`${key}`),false);
+	#for (var key in m.map) array_push(ret,m.map[key].key,false)
 
 	return ret
 }
 
 pub fn (m map) values() array {
 	ret := JS.makeEmptyArray()
-	#for (var key in m.map) array_push(ret,m.map[key],false);
+	#for (var key in m.map) array_push(ret,m.map[key].val,false);
 
 	return ret
 }
diff --git a/vlib/v/gen/js/auto_str_methods.v b/vlib/v/gen/js/auto_str_methods.v
index 4418aeb8d6..69aa06375d 100644
--- a/vlib/v/gen/js/auto_str_methods.v
+++ b/vlib/v/gen/js/auto_str_methods.v
@@ -610,7 +610,7 @@ fn (mut g JsGen) gen_str_for_map(info ast.Map, styp string, str_fn_name string)
 	g.definitions.writeln('\tlet keys = Object.keys(m.map);')
 	g.definitions.writeln('\tfor (let j = 0; j < keys.length;j++) {')
 	g.definitions.writeln('\t\tlet key = keys[j];')
-	g.definitions.writeln('\t\tlet value = m.map[key];')
+	g.definitions.writeln('\t\tlet value = m.map[key].val;')
 	g.definitions.writeln('\t\tkey = new ${key_styp}(key);')
 	if key_sym.kind == .string {
 		g.definitions.writeln('\t\tstrings__Builder_write_string(sb, new string("\'" + key.str + "\'"));')
diff --git a/vlib/v/gen/js/js.v b/vlib/v/gen/js/js.v
index 551a63d8b5..c3fc0713a4 100644
--- a/vlib/v/gen/js/js.v
+++ b/vlib/v/gen/js/js.v
@@ -1328,7 +1328,7 @@ fn (mut g JsGen) gen_assign_stmt(stmt ast.AssignStmt, semicolon bool) {
 					g.expr(left.left)
 					g.write('.map[')
 					g.expr(left.index)
-					g.write('.\$toJS()] = ')
+					g.write('.\$toJS()] = { val: ')
 				} else {
 					g.write('.arr.set(')
 					g.write('new int(')
@@ -1426,6 +1426,11 @@ fn (mut g JsGen) gen_assign_stmt(stmt ast.AssignStmt, semicolon bool) {
 			if array_set && !map_set {
 				g.write(')')
 			}
+			if left is ast.IndexExpr && left.is_map {
+				g.write(', key: ')
+				g.expr(left.index)
+				g.write(' }')
+			}
 			if semicolon {
 				if g.inside_loop {
 					g.write('; ')
@@ -1511,7 +1516,7 @@ fn (mut g JsGen) gen_enum_decl(it ast.EnumDecl) {
 		if field.has_expr && field.expr is ast.IntegerLiteral {
 			i = field.expr.val.int()
 		}
-		g.writeln('${i},')
+		g.writeln('new int(${i}),')
 		i++
 	}
 	g.dec_indent()
@@ -1707,7 +1712,7 @@ fn (mut g JsGen) gen_for_in_stmt(it ast.ForInStmt) {
 			g.writeln('for (var ${tmp2} in ${tmp}.map) {')
 
 			g.inc_indent()
-			g.writeln('let ${val} = ${tmp}.map[${tmp2}];')
+			g.writeln('let ${val} = ${tmp}.map[${tmp2}].val;')
 			sym := g.table.sym(it.key_type)
 			if sym.is_number() {
 				g.writeln('let ${key} = new ${g.styp(it.key_type)}(+${tmp2})')
@@ -3216,8 +3221,11 @@ fn (mut g JsGen) gen_map_init_expr(it ast.MapInit) {
 			g.write('[')
 			g.expr(key)
 			g.write('.\$toJS()]')
-			g.write(': ')
+			g.write(': { val: ')
 			g.expr(val)
+			g.write(', key: ')
+			g.expr(key)
+			g.write(' }')
 			if i < it.keys.len - 1 {
 				g.write(',')
 			}
diff --git a/vlib/v/gen/js/tests/map.v b/vlib/v/gen/js/tests/map.v
index 042c725116..1f03b73f67 100644
--- a/vlib/v/gen/js/tests/map.v
+++ b/vlib/v/gen/js/tests/map.v
@@ -1,8 +1,17 @@
+type T0 = int | string
+type T1 = T0 | rune
+
 struct Point {
 	x f64
 	y f64
 }
 
+enum Colors {
+	red = 1
+	green
+	blue
+}
+
 fn generic_map[T](items map[string]T) []T {
 	return items.values()
 }
@@ -226,17 +235,111 @@ fn test_map_len() {
 	assert items_2.len == 2
 }
 
-fn test_rune_keys() {
-	mut m := {
+fn test_map_with_different_key_types() {
+	// map[int]string
+	mut items_1 := {
+		1: 'one'
+		2: 'two'
+		3: 'three'
+	}
+	assert typeof(items_1).name == 'map[int]string'
+	assert items_1[2] == 'two'
+	items_1[4] = 'four'
+	assert items_1[4].len == 4
+	keys_1 := items_1.keys()
+	assert keys_1.contains(1)
+	assert keys_1.contains(2)
+	assert keys_1.contains(3)
+	assert keys_1.contains(4)
+	assert '${items_1}' == "{1: 'one', 2: 'two', 3: 'three', 4: 'four'}"
+
+	// map[string]int
+	mut items_2 := {
+		'one':   1
+		'two':   2
+		'three': 3
+	}
+	assert typeof(items_2).name == 'map[string]int'
+	assert items_2['two'] == 2
+	items_2['four'] = 4
+	assert items_2['four'] == 4
+	keys_2 := items_2.keys()
+	assert keys_2.contains('one')
+	assert keys_2.contains('two')
+	assert keys_2.contains('three')
+	assert keys_2.contains('four')
+	assert '${items_2}' == "{'one': 1, 'two': 2, 'three': 3, 'four': 4}"
+
+	// map[f64]string
+	mut items_3 := {
+		1.1: 'one dot one'
+		2.2: 'two dot two'
+		3.3: 'three dot three'
+	}
+	assert typeof(items_3).name == 'map[f64]string'
+	assert items_3[2.2] == 'two dot two'
+	items_3[4.4] = 'four dot four'
+	assert items_3[4.4].len == 13
+	keys_3 := items_3.keys()
+	assert keys_3.contains(1.1)
+	assert keys_3.contains(2.2)
+	assert keys_3.contains(3.3)
+	assert keys_3.contains(4.4)
+	assert '${items_3}' == "{1.1: 'one dot one', 2.2: 'two dot two', 3.3: 'three dot three', 4.4: 'four dot four'}"
+
+	// map[u8]string
+	mut items_4 := {
+		u8(1): 'one'
+		2:     'two'
+	}
+	assert typeof(items_4).name == 'map[u8]string'
+	assert items_4[2] == 'two'
+	items_4[3] = 'three'
+	assert items_4[3].len == 5
+	keys_4 := items_4.keys()
+	assert keys_4.contains(1)
+	assert keys_4.contains(2)
+	assert keys_4.contains(3)
+	assert '${items_4}' == "{49: 'one', 50: 'two', 51: 'three'}"
+
+	// map[rune]int
+	mut items_5 := {
 		`!`: 2
 		`%`: 3
 	}
-	assert typeof(m).name == 'map[rune]int'
-	assert m[`!`] == 2
-	m[`@`] = 7
-	assert m.len == 3
-	println(m)
-	assert '${m}' == '{`!`: 2, `%`: 3, `@`: 7}'
+	assert typeof(items_5).name == 'map[rune]int'
+	assert items_5[`!`] == 2
+	items_5[`@`] = 7
+	assert items_5.len == 3
+	keys_5 := items_5.keys()
+	assert keys_5.contains(`!`)
+	assert keys_5.contains(`%`)
+	assert keys_5.contains(`@`)
+	assert '${items_5}' == '{`!`: 2, `%`: 3, `@`: 7}'
+
+	// map[sum-type]string
+	mut items_6 := {
+		T1(T0(1)): 'one'
+		T0('2'):   'two'
+	}
+	items_6[`!`] = 'exclamation'
+	assert items_6[`!`].len == 11
+	keys_6 := items_6.keys()
+	assert keys_6.contains(T0(1))
+	assert keys_6.contains(T0('2'))
+	assert keys_6.contains(`!`)
+
+	// map[enum-type]string
+	mut items_7 := {
+		Colors.red: 'red'
+		.green:     'green'
+	}
+	items_7[.blue] = 'blue'
+	assert items_7[.blue].len == 4
+	keys_7 := items_7.keys()
+	keys_7.contains(.red)
+	keys_7.contains(.green)
+	keys_7.contains(.blue)
 }
 
 fn main() {
@@ -246,5 +349,5 @@ fn main() {
 	test_keys_method_with_generic_constraints()
 	test_direct_map_access()
 	test_map_len()
-	test_rune_keys()
+	test_map_with_different_key_types()
 }