From 11e25bc9ea30ffde14bcd51d79ced465e3dcb4e2 Mon Sep 17 00:00:00 2001
From: Gonzalo Chumillas <gchumillas@users.noreply.github.com>
Date: Fri, 18 Apr 2025 10:52:07 +0100
Subject: [PATCH] jsgen: fix array type checking in sum type match expressions
 (fix #24237 ) (#24259)

---
 vlib/v/gen/js/js.v                     |  8 +++++++-
 vlib/v/gen/js/tests/testdata/match.out |  6 +++++-
 vlib/v/gen/js/tests/testdata/match.v   | 22 ++++++++++++++++++++++
 3 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/vlib/v/gen/js/js.v b/vlib/v/gen/js/js.v
index 3aa1cc3967..7bc7fdb28f 100644
--- a/vlib/v/gen/js/js.v
+++ b/vlib/v/gen/js/js.v
@@ -561,7 +561,7 @@ fn (mut g JsGen) js_name(name_ string) string {
 		name = name[3..]
 		return name
 	}
-	name = name_.replace('.', '__')
+	name = name_.replace('[]', '').replace('.', '__')
 	if name in js_reserved {
 		return '_v_${name}'
 	}
@@ -2511,6 +2511,12 @@ fn (mut g JsGen) match_expr_sumtype(node ast.MatchExpr, is_expr bool, cond_var M
 						if tsym.language == .js && (tsym.name == 'JS.Number'
 							|| tsym.name == 'JS.Boolean' || tsym.name == 'JS.String') {
 							g.write(' === "${tsym.name[3..].to_lower_ascii()}"')
+						} else if tsym.kind == .array {
+							g.write(' && ')
+							g.match_cond(cond_var)
+							g.write('.arr.arr.every(x => x instanceof ')
+							g.expr(branch.exprs[sumtype_index])
+							g.write(')')
 						} else {
 							g.write(' instanceof ')
 							g.expr(branch.exprs[sumtype_index])
diff --git a/vlib/v/gen/js/tests/testdata/match.out b/vlib/v/gen/js/tests/testdata/match.out
index 19adfb61b7..02034c9446 100644
--- a/vlib/v/gen/js/tests/testdata/match.out
+++ b/vlib/v/gen/js/tests/testdata/match.out
@@ -2,4 +2,8 @@ Vec2d(42,43)
 Vec2d(46,74,21)
 life
 V is running on JS
-c:
\ No newline at end of file
+c:
+sum is int
+sum is string
+sum is Vec2d
+sum is []Vec2d
\ No newline at end of file
diff --git a/vlib/v/gen/js/tests/testdata/match.v b/vlib/v/gen/js/tests/testdata/match.v
index a43419fcc5..61796f1b1b 100644
--- a/vlib/v/gen/js/tests/testdata/match.v
+++ b/vlib/v/gen/js/tests/testdata/match.v
@@ -10,6 +10,7 @@ struct Vec3d {
 }
 
 type Vec = Vec2d | Vec3d
+type SumType = int | string | Vec2d | []Vec2d
 
 fn match_vec(v Vec) {
 	match v {
@@ -63,10 +64,31 @@ fn match_bool_cond() {
 	})
 }
 
+fn match_sum_type(sum SumType) {
+	match sum {
+		int {
+			println('sum is int')
+		}
+		string {
+			println('sum is string')
+		}
+		Vec2d {
+			println('sum is Vec2d')
+		}
+		[]Vec2d {
+			println('sum is []Vec2d')
+		}
+	}
+}
+
 fn main() {
 	match_vec(Vec2d{42, 43})
 	match_vec(Vec3d{46, 74, 21})
 	match_classic_num()
 	match_classic_string()
 	match_bool_cond()
+	match_sum_type(42)
+	match_sum_type('everything')
+	match_sum_type(Vec2d{7, 11})
+	match_sum_type([Vec2d{7, 11}, Vec2d{13, 17}])
 }