From 41690ac8530095f5ed693ccdd8f8e683010eeac6 Mon Sep 17 00:00:00 2001
From: shiroyk <kumoocat@gmail.com>
Date: Tue, 6 Aug 2024 21:46:34 +0800
Subject: [PATCH] Fix Array.prototype.toSpliced

---
 builtin_array.go       | 21 +++++++++------------
 builtin_arrray_test.go | 24 +++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 13 deletions(-)

diff --git a/builtin_array.go b/builtin_array.go
index 0993a16..0ebcdff 100644
--- a/builtin_array.go
+++ b/builtin_array.go
@@ -1338,11 +1338,9 @@ func (r *Runtime) arrayproto_toSpliced(call FunctionCall) Value {
 	length := toLength(o.self.getStr("length", nil))
 	actualStart := relToIdx(call.Argument(0).ToInteger(), length)
 	var actualSkipCount int64
-	switch len(call.Arguments) {
-	case 0:
-	case 1:
+	if len(call.Arguments) == 1 {
 		actualSkipCount = length - actualStart
-	default:
+	} else if len(call.Arguments) > 1 {
 		actualSkipCount = min(max(call.Argument(1).ToInteger(), 0), length-actualStart)
 	}
 	itemCount := max(int64(len(call.Arguments)-2), 0)
@@ -1354,24 +1352,23 @@ func (r *Runtime) arrayproto_toSpliced(call FunctionCall) Value {
 	if src := r.checkStdArrayObj(o); src != nil {
 		var values []Value
 		if itemCount < actualSkipCount {
-			values = src.values
+			values = make([]Value, len(src.values))
+			copy(values, src.values)
 			copy(values[actualStart+itemCount:], values[actualStart+actualSkipCount:])
-			tail := values[newLength:]
-			for k := range tail {
-				tail[k] = nil
-			}
 			values = values[:newLength]
 		} else if itemCount > actualSkipCount {
 			if int64(cap(src.values)) >= newLength {
-				values = src.values[:newLength]
-				copy(values[actualStart+itemCount:], values[actualStart+actualSkipCount:length])
+				values = make([]Value, newLength)
+				copy(values, src.values[:actualStart])
+				copy(values[actualStart+itemCount:], src.values[actualStart+actualSkipCount:])
 			} else {
 				values = make([]Value, newLength)
 				copy(values, src.values[:actualStart])
 				copy(values[actualStart+itemCount:], src.values[actualStart+actualSkipCount:])
 			}
 		} else {
-			values = src.values
+			values = make([]Value, len(src.values))
+			copy(values, src.values)
 		}
 		if itemCount > 0 {
 			copy(values[actualStart:], call.Arguments[2:])
diff --git a/builtin_arrray_test.go b/builtin_arrray_test.go
index 8418a95..3600347 100644
--- a/builtin_arrray_test.go
+++ b/builtin_arrray_test.go
@@ -1,6 +1,8 @@
 package sobek
 
-import "testing"
+import (
+	"testing"
+)
 
 func TestArrayProtoProp(t *testing.T) {
 	const SCRIPT = `
@@ -339,3 +341,23 @@ func TestArrayProto(t *testing.T) {
 	`
 	testScriptWithTestLib(SCRIPT, _undefined, t)
 }
+
+func TestArrayToSpliced(t *testing.T) {
+	const SCRIPT = `
+	const a = [1, 2, 3];
+	a.push(4)
+	assert(compareArray(a, [1, 2, 3, 4]));
+	const b = a.toSpliced(2)
+	assert(compareArray(a, [1, 2, 3, 4]));
+	assert(compareArray(b, [1, 2]));
+	a.push(5)
+	const c = a.toSpliced(1, 2);
+	assert(compareArray(a, [1, 2, 3, 4, 5]));
+	assert(compareArray(c, [1, 4, 5]));
+	assert(compareArray(a.toSpliced(4, 2, 'a', 'b'), [1, 2, 3, 4, 'a', 'b']));
+	assert(compareArray(a.toSpliced(-2, 2), [1, 2, 3]));
+	assert(compareArray(a.toSpliced(2, 10), [1, 2]));
+	assert(compareArray(a.toSpliced(1, 0, 'a'), [1, 'a', 2, 3, 4, 5]));
+	`
+	testScriptWithTestLib(SCRIPT, _undefined, t)
+}