diff --git a/napi/src/env.rs b/napi/src/env.rs
index 236e4d83..9c37a071 100644
--- a/napi/src/env.rs
+++ b/napi/src/env.rs
@@ -179,17 +179,19 @@ impl Env {
     check_status(status)?;
     mem::forget(data);
 
-    let mut buffer = JsBuffer::from_raw_unchecked(self.0, raw_value);
-    buffer.data = data_ptr as *const u8;
-    buffer.len = length;
-    Ok(buffer)
+    Ok(JsBuffer::from_raw_unchecked(
+      self.0,
+      raw_value,
+      data_ptr as *mut u8,
+      length as usize,
+    ))
   }
 
   #[inline]
-  pub fn create_buffer_with_data(&self, data: Vec<u8>) -> Result<JsBuffer> {
+  pub fn create_buffer_with_data(&self, mut data: Vec<u8>) -> Result<JsBuffer> {
     let length = data.len() as u64;
     let mut raw_value = ptr::null_mut();
-    let data_ptr = data.as_ptr();
+    let data_ptr = data.as_mut_ptr();
     let status = unsafe {
       sys::napi_create_external_buffer(
         self.0,
@@ -206,10 +208,12 @@ impl Env {
       unsafe { sys::napi_adjust_external_memory(self.0, length as i64, &mut changed) };
     check_status(adjust_external_memory_status)?;
     mem::forget(data);
-    let mut buffer = JsBuffer::from_raw_unchecked(self.0, raw_value);
-    buffer.data = data_ptr as *const u8;
-    buffer.len = length;
-    Ok(buffer)
+    Ok(JsBuffer::from_raw_unchecked(
+      self.0,
+      raw_value,
+      data_ptr,
+      length as usize,
+    ))
   }
 
   #[inline]
diff --git a/napi/src/js_values/arraybuffer.rs b/napi/src/js_values/arraybuffer.rs
index c5b40617..a058c824 100644
--- a/napi/src/js_values/arraybuffer.rs
+++ b/napi/src/js_values/arraybuffer.rs
@@ -4,7 +4,7 @@ use super::{JsObject, NapiValue, Value, ValueType};
 use crate::error::check_status;
 use crate::{sys, Result};
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct JsArrayBuffer {
   pub value: JsObject,
   pub data: *const u8,
diff --git a/napi/src/js_values/boolean.rs b/napi/src/js_values/boolean.rs
index b9ab7142..d4f43cc2 100644
--- a/napi/src/js_values/boolean.rs
+++ b/napi/src/js_values/boolean.rs
@@ -4,7 +4,7 @@ use super::Value;
 use crate::error::check_status;
 use crate::{sys, Error, Result};
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct JsBoolean(pub(crate) Value);
 
 impl JsBoolean {
diff --git a/napi/src/js_values/buffer.rs b/napi/src/js_values/buffer.rs
index 1c70f80f..8091ae5a 100644
--- a/napi/src/js_values/buffer.rs
+++ b/napi/src/js_values/buffer.rs
@@ -1,4 +1,4 @@
-use std::ops::{Deref, DerefMut};
+use std::ops::Deref;
 use std::ptr;
 use std::slice;
 
@@ -6,23 +6,26 @@ use super::{JsObject, JsUnknown, NapiValue, Value, ValueType};
 use crate::error::check_status;
 use crate::{sys, Result};
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct JsBuffer {
   pub value: JsObject,
-  pub data: *const u8,
-  pub len: u64,
+  pub data: &'static [u8],
 }
 
 impl JsBuffer {
-  pub(crate) fn from_raw_unchecked(env: sys::napi_env, value: sys::napi_value) -> Self {
+  pub(crate) fn from_raw_unchecked(
+    env: sys::napi_env,
+    value: sys::napi_value,
+    data: *mut u8,
+    len: usize,
+  ) -> Self {
     Self {
       value: JsObject(Value {
         env,
         value,
         value_type: ValueType::Object,
       }),
-      data: ptr::null(),
-      len: 0,
+      data: unsafe { slice::from_raw_parts_mut(data, len) },
     }
   }
 
@@ -47,15 +50,14 @@ impl NapiValue for JsBuffer {
         value,
         value_type: ValueType::Object,
       }),
-      data: data as *const u8,
-      len,
+      data: unsafe { slice::from_raw_parts_mut(data as *mut _, len as usize) },
     })
   }
 }
 
 impl AsRef<[u8]> for JsBuffer {
   fn as_ref(&self) -> &[u8] {
-    self.deref()
+    self.data
   }
 }
 
@@ -63,12 +65,6 @@ impl Deref for JsBuffer {
   type Target = [u8];
 
   fn deref(&self) -> &[u8] {
-    unsafe { slice::from_raw_parts(self.data, self.len as usize) }
-  }
-}
-
-impl DerefMut for JsBuffer {
-  fn deref_mut(&mut self) -> &mut [u8] {
-    unsafe { slice::from_raw_parts_mut(self.data as *mut _, self.len as usize) }
+    self.data
   }
 }
diff --git a/napi/src/js_values/class_property.rs b/napi/src/js_values/class_property.rs
index 73cbfeda..2f57eea6 100644
--- a/napi/src/js_values/class_property.rs
+++ b/napi/src/js_values/class_property.rs
@@ -2,7 +2,7 @@ use std::ptr;
 
 use crate::{sys, Callback, Env, NapiValue, Result};
 
-#[derive(Clone, Debug)]
+#[derive(Debug)]
 pub struct Property {
   name: String,
   raw_descriptor: sys::napi_property_descriptor,
diff --git a/napi/src/js_values/function.rs b/napi/src/js_values/function.rs
index 7f3a6c8e..c3497efa 100644
--- a/napi/src/js_values/function.rs
+++ b/napi/src/js_values/function.rs
@@ -5,7 +5,7 @@ use super::Value;
 use crate::error::check_status;
 use crate::{sys, Env, Error, JsObject, JsUnknown, NapiValue, Result, Status};
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct JsFunction(pub(crate) Value);
 
 /// See [Working with JavaScript Functions](https://nodejs.org/api/n-api.html#n_api_working_with_javascript_functions).
diff --git a/napi/src/js_values/mod.rs b/napi/src/js_values/mod.rs
index 63fc7cf1..f0963d25 100644
--- a/napi/src/js_values/mod.rs
+++ b/napi/src/js_values/mod.rs
@@ -35,20 +35,20 @@ pub(crate) use value_ref::Ref;
 pub use value_type::ValueType;
 
 // Value types
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct JsUnknown(pub(crate) Value);
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct JsNull(pub(crate) Value);
 
 #[cfg(napi6)]
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct JsBigint(pub(crate) Value);
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct JsSymbol(pub(crate) Value);
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct JsExternal(pub(crate) Value);
 
 #[inline]
diff --git a/napi/src/js_values/number.rs b/napi/src/js_values/number.rs
index c0486aab..81ae1abe 100644
--- a/napi/src/js_values/number.rs
+++ b/napi/src/js_values/number.rs
@@ -4,7 +4,7 @@ use super::Value;
 use crate::error::check_status;
 use crate::{sys, Error, Result};
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct JsNumber(pub(crate) Value);
 
 impl TryFrom<JsNumber> for usize {
diff --git a/napi/src/js_values/object.rs b/napi/src/js_values/object.rs
index c81b4ad6..0a1144d4 100644
--- a/napi/src/js_values/object.rs
+++ b/napi/src/js_values/object.rs
@@ -5,7 +5,7 @@ use super::Value;
 use crate::error::check_status;
 use crate::{sys, Env, Error, JsBuffer, JsNumber, JsString, NapiValue, Result, Status};
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct JsObject(pub(crate) Value);
 
 impl JsObject {
diff --git a/napi/src/js_values/string.rs b/napi/src/js_values/string.rs
index 1587582b..da8f599f 100644
--- a/napi/src/js_values/string.rs
+++ b/napi/src/js_values/string.rs
@@ -8,7 +8,7 @@ use super::Value;
 use crate::error::check_status;
 use crate::{sys, Error, Result, Status};
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct JsString(pub(crate) Value);
 
 impl JsString {
diff --git a/napi/src/js_values/undefined.rs b/napi/src/js_values/undefined.rs
index adafb5d0..4f32b746 100644
--- a/napi/src/js_values/undefined.rs
+++ b/napi/src/js_values/undefined.rs
@@ -1,4 +1,4 @@
 use super::Value;
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct JsUndefined(pub(crate) Value);
diff --git a/napi/src/js_values/value.rs b/napi/src/js_values/value.rs
index d4d3645c..fb9f8137 100644
--- a/napi/src/js_values/value.rs
+++ b/napi/src/js_values/value.rs
@@ -2,7 +2,7 @@ use crate::sys;
 
 use super::ValueType;
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 pub struct Value {
   pub env: sys::napi_env,
   pub value: sys::napi_value,
diff --git a/napi/src/lib.rs b/napi/src/lib.rs
index b34fc603..686e0485 100644
--- a/napi/src/lib.rs
+++ b/napi/src/lib.rs
@@ -159,7 +159,7 @@ macro_rules! register_module {
           let hook_result = Ok(());
 
           match hook_result.and_then(move |_| result) {
-            Ok(_) => exports.raw_value(),
+            Ok(_) => cjs_module.exports.raw_value(),
             Err(e) => {
               unsafe {
                 sys::napi_throw_error(
diff --git a/test_module/src/function.rs b/test_module/src/function.rs
index 733f7f8e..ef9a9596 100644
--- a/test_module/src/function.rs
+++ b/test_module/src/function.rs
@@ -1,4 +1,4 @@
-use napi::{JsFunction, CallContext, JsNull, Result, JsObject};
+use napi::{CallContext, JsFunction, JsNull, JsObject, Result};
 
 #[js_function(1)]
 pub fn call_function(ctx: CallContext) -> Result<JsNull> {
@@ -13,10 +13,10 @@ pub fn call_function(ctx: CallContext) -> Result<JsNull> {
 
 #[js_function(1)]
 pub fn call_function_with_this(ctx: CallContext<JsObject>) -> Result<JsNull> {
-  let js_this = ctx.this;
+  let js_this = &ctx.this;
   let js_func = ctx.get::<JsFunction>(0)?;
 
-  js_func.call(Some(&js_this), &[])?;
+  js_func.call(Some(js_this), &[])?;
 
   ctx.env.get_null()
 }