1 files changed, 27 insertions, 0 deletions
diff --git a/resolvers/deno/npm/local.rs b/resolvers/deno/npm/local.rs
new file mode 100644
index 000000000..aef476ad9
--- /dev/null
+++ b/resolvers/deno/npm/local.rs
@@ -0,0 +1,27 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+
+use std::borrow::Cow;
+
+/// Normalizes a package name for use at `node_modules/.deno/<pkg-name>@<version>[_<copy_index>]`
+pub fn normalize_pkg_name_for_node_modules_deno_folder(name: &str) -> Cow<str> {
+  let name = if name.to_lowercase() == name {
+    Cow::Borrowed(name)
+  } else {
+    Cow::Owned(format!("_{}", mixed_case_package_name_encode(name)))
+  };
+  if name.starts_with('@') {
+    name.replace('/', "+").into()
+  } else {
+    name
+  }
+}
+
+fn mixed_case_package_name_encode(name: &str) -> String {
+  // use base32 encoding because it's reversible and the character set
+  // only includes the characters within 0-9 and A-Z so it can be lower cased
+  base32::encode(
+    base32::Alphabet::Rfc4648Lower { padding: false },
+    name.as_bytes(),
+  )
+  .to_lowercase()
+}