From 34f1f0dc75eb2e87112234fa26423c15cb9f4052 Mon Sep 17 00:00:00 2001
From: Lars Bahner <lars.bahner@gmail.com>
Date: Sun, 28 Jan 2024 10:19:51 +0100
Subject: [PATCH 1/2] js can't support filewriter on wasm

---
 files/filewriter_unix.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/files/filewriter_unix.go b/files/filewriter_unix.go
index cd99aeb9a..c808a773b 100644
--- a/files/filewriter_unix.go
+++ b/files/filewriter_unix.go
@@ -1,4 +1,5 @@
-//go:build darwin || linux || netbsd || openbsd || freebsd || dragonfly || js || wasip1
+//go:build darwin || linux || netbsd || openbsd || freebsd || dragonfly || (js && !wasm) || wasip1
+// +build darwin linux netbsd openbsd freebsd dragonfly js,!wasm wasip1
 
 package files
 

From 68fa6cc904ecee95ffd792d9606710d0d2ded39f Mon Sep 17 00:00:00 2001
From: Lars Bahner <lars.bahner@gmail.com>
Date: Sun, 28 Jan 2024 10:32:26 +0100
Subject: [PATCH 2/2] Add wasm filewriter

---
 files/filewriter_unix_test.go |  4 +++-
 files/filewriter_wasm.go      | 27 +++++++++++++++++++++++++++
 files/filewriter_wasm_test.go | 30 ++++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100644 files/filewriter_wasm.go
 create mode 100644 files/filewriter_wasm_test.go

diff --git a/files/filewriter_unix_test.go b/files/filewriter_unix_test.go
index 9f63fe0fe..23b47f01c 100644
--- a/files/filewriter_unix_test.go
+++ b/files/filewriter_unix_test.go
@@ -1,4 +1,6 @@
-//go:build darwin || linux || netbsd || openbsd || freebsd || dragonfly || js || wasip1
+//go:build darwin || linux || netbsd || openbsd || freebsd || dragonfly || (js && !wasm) || wasip1
+// +build darwin linux netbsd openbsd freebsd dragonfly js,!wasm wasip1
+
 
 package files
 
diff --git a/files/filewriter_wasm.go b/files/filewriter_wasm.go
new file mode 100644
index 000000000..4c49c7c50
--- /dev/null
+++ b/files/filewriter_wasm.go
@@ -0,0 +1,27 @@
+//go:build js && wasm
+// +build js,wasm
+
+package files
+
+import (
+	"errors"
+	"os"
+	"strings"
+)
+
+// In a WebAssembly context, direct file system operations like in Unix are not possible.
+// Therefore, these functions could be adapted to work with in-memory storage or
+// interfacing with JavaScript for file operations.
+
+func createNewFile(path string) (*os.File, error) {
+	// Since direct file creation isn't possible, you might want to simulate it or
+	// interface with JavaScript. For now, this will return an error.
+	return nil, errors.New("createNewFile is not supported in WebAssembly environments")
+}
+
+func isValidFilename(filename string) bool {
+	// Filename validation might still be relevant in a WASM context.
+	// You can keep the logic same or adapt it based on your application's needs.
+	invalidChars := `/` + "\x00"
+	return !strings.ContainsAny(filename, invalidChars)
+}
diff --git a/files/filewriter_wasm_test.go b/files/filewriter_wasm_test.go
new file mode 100644
index 000000000..29730bfcb
--- /dev/null
+++ b/files/filewriter_wasm_test.go
@@ -0,0 +1,30 @@
+//go:build js && wasm
+// +build js,wasm
+
+package files
+
+import (
+    "testing"
+    "github.com/stretchr/testify/assert"
+)
+
+func TestIsValidFilenameWASM(t *testing.T) {
+    // Since file creation isn't supported in WASM, this test only focuses on filename validation.
+
+    testCases := []struct {
+        name     string
+        valid    bool
+    }{
+        {"validfilename", true},
+        {"/invalid/filename", false},
+        {"", false},
+        {".", false},
+        {"..", false},
+    }
+
+    for _, tc := range testCases {
+        t.Run(tc.name, func(t *testing.T) {
+            assert.Equal(t, tc.valid, isValidFilename(tc.name))
+        })
+    }
+}