diff --git a/src/async_wrap.cc b/src/async_wrap.cc
index 47a99551275e17..70fc86702f0b10 100644
--- a/src/async_wrap.cc
+++ b/src/async_wrap.cc
@@ -22,7 +22,6 @@
 #include "async_wrap-inl.h"
 #include "env-inl.h"
 #include "node_errors.h"
-#include "node_internals.h"
 #include "tracing/traced_value.h"
 #include "util-inl.h"
 
diff --git a/src/cares_wrap.cc b/src/cares_wrap.cc
index 09cf809dec3dd2..57c02fb32653e5 100644
--- a/src/cares_wrap.cc
+++ b/src/cares_wrap.cc
@@ -24,7 +24,6 @@
 #include "async_wrap-inl.h"
 #include "env-inl.h"
 #include "node.h"
-#include "node_internals.h"
 #include "req_wrap-inl.h"
 #include "util-inl.h"
 #include "uv.h"
diff --git a/src/connection_wrap.cc b/src/connection_wrap.cc
index db239f9becdb53..67308bdb9c8d95 100644
--- a/src/connection_wrap.cc
+++ b/src/connection_wrap.cc
@@ -3,7 +3,6 @@
 #include "connect_wrap.h"
 #include "env-inl.h"
 #include "pipe_wrap.h"
-#include "node_internals.h"
 #include "stream_base-inl.h"
 #include "stream_wrap.h"
 #include "tcp_wrap.h"
diff --git a/src/debug_utils.cc b/src/debug_utils.cc
index d9db2d52e0db85..6dac86f002b07d 100644
--- a/src/debug_utils.cc
+++ b/src/debug_utils.cc
@@ -1,5 +1,4 @@
 #include "debug_utils.h"
-#include "node_internals.h"
 
 #ifdef __POSIX__
 #if defined(__linux__)
diff --git a/src/debug_utils.h b/src/debug_utils.h
index ed5e42fcbe8e6e..7e8a23d3ae309e 100644
--- a/src/debug_utils.h
+++ b/src/debug_utils.h
@@ -4,9 +4,10 @@
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
 #include "async_wrap.h"
-#include "env.h"
-#include <string>
+#include "env-inl.h"
+
 #include <sstream>
+#include <string>
 
 // Use FORCE_INLINE on functions that have a debug-category-enabled check first
 // and then ideally only a single function call following it, to maintain
diff --git a/src/fs_event_wrap.cc b/src/fs_event_wrap.cc
index 249a4bb973cbd7..acc83d017e0633 100644
--- a/src/fs_event_wrap.cc
+++ b/src/fs_event_wrap.cc
@@ -23,7 +23,6 @@
 #include "env-inl.h"
 #include "util-inl.h"
 #include "node.h"
-#include "node_internals.h"
 #include "handle_wrap.h"
 #include "string_bytes.h"
 
diff --git a/src/heap_utils.cc b/src/heap_utils.cc
index 84cbf07c1ee72e..a1ca118e6c1f93 100644
--- a/src/heap_utils.cc
+++ b/src/heap_utils.cc
@@ -1,5 +1,4 @@
-#include "node_internals.h"
-#include "env.h"
+#include "env-inl.h"
 
 using v8::Array;
 using v8::Boolean;
diff --git a/src/inspector_js_api.cc b/src/inspector_js_api.cc
index 0bf43c6fbb1a81..d94cf4173d19aa 100644
--- a/src/inspector_js_api.cc
+++ b/src/inspector_js_api.cc
@@ -1,7 +1,6 @@
 #include "base_object-inl.h"
 #include "inspector_agent.h"
 #include "inspector_io.h"
-#include "node_internals.h"
 #include "v8.h"
 #include "v8-inspector.h"
 
diff --git a/src/js_stream.cc b/src/js_stream.cc
index e4137079fa5aca..32dea04db5aeec 100644
--- a/src/js_stream.cc
+++ b/src/js_stream.cc
@@ -4,7 +4,6 @@
 #include "env-inl.h"
 #include "node_buffer.h"
 #include "node_errors.h"
-#include "node_internals.h"
 #include "stream_base-inl.h"
 #include "v8.h"
 
diff --git a/src/module_wrap.cc b/src/module_wrap.cc
index 243352fe644e40..8599029fea1f9f 100644
--- a/src/module_wrap.cc
+++ b/src/module_wrap.cc
@@ -7,7 +7,6 @@
 #include "node_errors.h"
 #include "node_url.h"
 #include "util-inl.h"
-#include "node_internals.h"
 #include "node_contextify.h"
 #include "node_watchdog.h"
 
diff --git a/src/node_binding.cc b/src/node_binding.cc
index 5ea8f01b41bb89..85f3c19e690182 100644
--- a/src/node_binding.cc
+++ b/src/node_binding.cc
@@ -1,6 +1,7 @@
 #include "node_binding.h"
-#include "node_internals.h"
+#include "env-inl.h"
 #include "node_native_module.h"
+#include "util.h"
 
 #if HAVE_OPENSSL
 #define NODE_BUILTIN_OPENSSL_MODULES(V) V(crypto) V(tls_wrap)
diff --git a/src/node_buffer.cc b/src/node_buffer.cc
index 2f4a4c66619e70..ccc338f94174aa 100644
--- a/src/node_buffer.cc
+++ b/src/node_buffer.cc
@@ -19,9 +19,10 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-#include "node.h"
 #include "node_buffer.h"
+#include "node.h"
 #include "node_errors.h"
+#include "node_internals.h"
 
 #include "env-inl.h"
 #include "string_bytes.h"
diff --git a/src/node_contextify.h b/src/node_contextify.h
index fedec0cd345d78..5f4f20554aed50 100644
--- a/src/node_contextify.h
+++ b/src/node_contextify.h
@@ -6,7 +6,6 @@
 #include "base_object-inl.h"
 #include "node_context_data.h"
 #include "node_errors.h"
-#include "node_internals.h"
 
 namespace node {
 namespace contextify {
diff --git a/src/node_crypto.cc b/src/node_crypto.cc
index bda172e2810a7a..920869a2f2becd 100644
--- a/src/node_crypto.cc
+++ b/src/node_crypto.cc
@@ -27,7 +27,6 @@
 #include "node_crypto_clienthello-inl.h"
 #include "node_crypto_groups.h"
 #include "node_errors.h"
-#include "node_internals.h"
 #include "node_mutex.h"
 #include "node_process.h"
 #include "tls_wrap.h"  // TLSWrap
diff --git a/src/node_domain.cc b/src/node_domain.cc
index b29ca1db0575a1..9075845442fd4d 100644
--- a/src/node_domain.cc
+++ b/src/node_domain.cc
@@ -1,5 +1,5 @@
+#include "env-inl.h"
 #include "v8.h"
-#include "node_internals.h"
 
 namespace node {
 namespace domain {
diff --git a/src/node_dtrace.cc b/src/node_dtrace.cc
index cd3986cef56a97..dfabde0747bdc9 100644
--- a/src/node_dtrace.cc
+++ b/src/node_dtrace.cc
@@ -43,7 +43,6 @@
 #endif
 
 #include "node_errors.h"
-#include "node_internals.h"
 
 #include <string.h>
 
diff --git a/src/node_dtrace.h b/src/node_dtrace.h
index d16e23ddb384b7..ee11cd68aa7630 100644
--- a/src/node_dtrace.h
+++ b/src/node_dtrace.h
@@ -24,7 +24,8 @@
 
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
-#include "node_internals.h"
+#include "env.h"
+#include "v8.h"
 
 extern "C" {
 /*
diff --git a/src/node_env_var.cc b/src/node_env_var.cc
index d1ebb064e2417e..63cba55ab567a8 100644
--- a/src/node_env_var.cc
+++ b/src/node_env_var.cc
@@ -1,6 +1,6 @@
 #include "node_errors.h"
-#include "node_internals.h"
 #include "node_process.h"
+#include "util.h"
 
 #ifdef __APPLE__
 #include <crt_externs.h>
diff --git a/src/node_file.cc b/src/node_file.cc
index 8757f6bf0d8921..35c8e01a28c0b5 100644
--- a/src/node_file.cc
+++ b/src/node_file.cc
@@ -22,9 +22,9 @@
 #include "node_file.h"
 #include "aliased_buffer.h"
 #include "node_buffer.h"
-#include "node_internals.h"
 #include "node_process.h"
 #include "node_stat_watcher.h"
+#include "util.h"
 
 #include "tracing/trace_event.h"
 
diff --git a/src/node_http2.cc b/src/node_http2.cc
index 1489d8b6f88b00..a3ce022835ea5a 100644
--- a/src/node_http2.cc
+++ b/src/node_http2.cc
@@ -4,8 +4,8 @@
 #include "node_buffer.h"
 #include "node_http2.h"
 #include "node_http2_state.h"
-#include "node_internals.h"
 #include "node_perf.h"
+#include "util.h"
 
 #include <algorithm>
 
diff --git a/src/node_http2.h b/src/node_http2.h
index 4dc33d84c2af61..8347510c9d0913 100644
--- a/src/node_http2.h
+++ b/src/node_http2.h
@@ -3,7 +3,10 @@
 
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
+// FIXME(joyeecheung): nghttp2.h needs stdint.h to compile on Windows
+#include <stdint.h>
 #include "nghttp2/nghttp2.h"
+
 #include "node_http2_state.h"
 #include "node_perf.h"
 #include "stream_base-inl.h"
diff --git a/src/node_http_parser_impl.h b/src/node_http_parser_impl.h
index 48d669a7593e6c..7a955cc1e9eca6 100644
--- a/src/node_http_parser_impl.h
+++ b/src/node_http_parser_impl.h
@@ -27,7 +27,7 @@
 
 #include "node.h"
 #include "node_buffer.h"
-#include "node_internals.h"
+#include "util.h"
 
 #include "async_wrap-inl.h"
 #include "env-inl.h"
diff --git a/src/node_i18n.cc b/src/node_i18n.cc
index c081bde93bec2a..edc7f56093a137 100644
--- a/src/node_i18n.cc
+++ b/src/node_i18n.cc
@@ -44,12 +44,13 @@
 
 #if defined(NODE_HAVE_I18N_SUPPORT)
 
+#include "base_object-inl.h"
+#include "env-inl.h"
 #include "node.h"
 #include "node_buffer.h"
 #include "node_errors.h"
-#include "env-inl.h"
+#include "node_internals.h"
 #include "util-inl.h"
-#include "base_object-inl.h"
 #include "v8.h"
 
 #include <unicode/utypes.h>
diff --git a/src/node_i18n.h b/src/node_i18n.h
index 7faa5e57ef25fb..a0a398ac818736 100644
--- a/src/node_i18n.h
+++ b/src/node_i18n.h
@@ -24,7 +24,8 @@
 
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
-#include "node_internals.h"
+#include "util.h"
+
 #include <string>
 
 #if defined(NODE_HAVE_I18N_SUPPORT)
diff --git a/src/node_internals.h b/src/node_internals.h
index 70c82dd2fcd2ce..0d4fe74ebf3d02 100644
--- a/src/node_internals.h
+++ b/src/node_internals.h
@@ -44,39 +44,9 @@
 #define Z_MIN_WINDOWBITS 8
 #define Z_MAX_WINDOWBITS 15
 #define Z_DEFAULT_WINDOWBITS 15
-// Fewer than 64 bytes per chunk is not recommended.
-// Technically it could work with as few as 8, but even 64 bytes
-// is low.  Usually a MB or more is best.
-#define Z_MIN_CHUNK 64
-#define Z_MAX_CHUNK std::numeric_limits<double>::infinity()
-#define Z_DEFAULT_CHUNK (16 * 1024)
-#define Z_MIN_MEMLEVEL 1
-#define Z_MAX_MEMLEVEL 9
-#define Z_DEFAULT_MEMLEVEL 8
-#define Z_MIN_LEVEL -1
-#define Z_MAX_LEVEL 9
-#define Z_DEFAULT_LEVEL Z_DEFAULT_COMPRESSION
 
 struct sockaddr;
 
-// Variation on NODE_DEFINE_CONSTANT that sets a String value.
-#define NODE_DEFINE_STRING_CONSTANT(target, name, constant)                   \
-  do {                                                                        \
-    v8::Isolate* isolate = target->GetIsolate();                              \
-    v8::Local<v8::String> constant_name =                                     \
-        v8::String::NewFromUtf8(isolate, name, v8::NewStringType::kNormal)    \
-            .ToLocalChecked();                                                \
-    v8::Local<v8::String> constant_value =                                    \
-        v8::String::NewFromUtf8(isolate, constant, v8::NewStringType::kNormal)\
-            .ToLocalChecked();                                                \
-    v8::PropertyAttribute constant_attributes =                               \
-        static_cast<v8::PropertyAttribute>(v8::ReadOnly | v8::DontDelete);    \
-    target->DefineOwnProperty(isolate->GetCurrentContext(),                   \
-                              constant_name,                                  \
-                              constant_value,                                 \
-                              constant_attributes).FromJust();                \
-  } while (0)
-
 namespace node {
 
 namespace native_module {
@@ -126,80 +96,10 @@ void RegisterSignalHandler(int signal,
 std::string GetHumanReadableProcessName();
 void GetHumanReadableProcessName(char (*name)[1024]);
 
-template <typename T, size_t N>
-constexpr size_t arraysize(const T(&)[N]) { return N; }
-
-#ifndef ROUND_UP
-# define ROUND_UP(a, b) ((a) % (b) ? ((a) + (b)) - ((a) % (b)) : (a))
-#endif
-
-#ifdef __GNUC__
-# define MUST_USE_RESULT __attribute__((warn_unused_result))
-#else
-# define MUST_USE_RESULT
-#endif
-
-class SlicedArguments {
- public:
-  inline explicit SlicedArguments(
-      const v8::FunctionCallbackInfo<v8::Value>& args,
-      size_t start = 0);
-  inline size_t size() const { return size_; }
-  inline v8::Local<v8::Value>* data() { return data_; }
-
- private:
-  size_t size_;
-  v8::Local<v8::Value>* data_;
-  v8::Local<v8::Value> fixed_[64];
-  std::vector<v8::Local<v8::Value>> dynamic_;
-};
-
-SlicedArguments::SlicedArguments(
-    const v8::FunctionCallbackInfo<v8::Value>& args,
-    size_t start) : size_(0), data_(fixed_) {
-  const size_t length = static_cast<size_t>(args.Length());
-  if (start >= length) return;
-  const size_t size = length - start;
-
-  if (size > arraysize(fixed_)) {
-    dynamic_.resize(size);
-    data_ = dynamic_.data();
-  }
-
-  for (size_t i = 0; i < size; ++i)
-    data_[i] = args[i + start];
-
-  size_ = size;
-}
-
 namespace task_queue {
 void PromiseRejectCallback(v8::PromiseRejectMessage message);
 }  // namespace task_queue
 
-enum Endianness {
-  kLittleEndian,  // _Not_ LITTLE_ENDIAN, clashes with endian.h.
-  kBigEndian
-};
-
-inline enum Endianness GetEndianness() {
-  // Constant-folded by the compiler.
-  const union {
-    uint8_t u8[2];
-    uint16_t u16;
-  } u = {
-    { 1, 0 }
-  };
-  return u.u16 == 1 ? kLittleEndian : kBigEndian;
-}
-
-inline bool IsLittleEndian() {
-  return GetEndianness() == kLittleEndian;
-}
-
-inline bool IsBigEndian() {
-  return GetEndianness() == kBigEndian;
-}
-
 class ArrayBufferAllocator : public v8::ArrayBuffer::Allocator {
  public:
   inline uint32_t* zero_fill_field() { return &zero_fill_field_; }
diff --git a/src/node_messaging.cc b/src/node_messaging.cc
index a538839bcc6fcb..aa4b92bf749eac 100644
--- a/src/node_messaging.cc
+++ b/src/node_messaging.cc
@@ -4,7 +4,6 @@
 #include "debug_utils.h"
 #include "node_buffer.h"
 #include "node_errors.h"
-#include "node_internals.h"
 #include "node_process.h"
 #include "util-inl.h"
 #include "util.h"
diff --git a/src/node_native_module.cc b/src/node_native_module.cc
index 012e50b9e814f0..f272dd46bef635 100644
--- a/src/node_native_module.cc
+++ b/src/node_native_module.cc
@@ -1,6 +1,5 @@
 #include "node_native_module.h"
 #include "node_errors.h"
-#include "node_internals.h"
 
 namespace node {
 
diff --git a/src/node_options.cc b/src/node_options.cc
index 667d7b6b9ddc60..a3a5e0233aa67c 100644
--- a/src/node_options.cc
+++ b/src/node_options.cc
@@ -1,5 +1,6 @@
 #include <errno.h>
-#include "node_internals.h"
+#include "env-inl.h"
+#include "node_binding.h"
 #include "node_options-inl.h"
 
 using v8::Boolean;
diff --git a/src/node_os.cc b/src/node_os.cc
index 505f42daf67fe4..4a372f4e428491 100644
--- a/src/node_os.cc
+++ b/src/node_os.cc
@@ -19,8 +19,9 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-#include "node_internals.h"
+#include "env-inl.h"
 #include "string_bytes.h"
+#include "util.h"
 
 #include <array>
 #include <errno.h>
diff --git a/src/node_perf.h b/src/node_perf.h
index 703ef81ce48def..fe418ad441718a 100644
--- a/src/node_perf.h
+++ b/src/node_perf.h
@@ -4,7 +4,6 @@
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
 #include "node.h"
-#include "node_internals.h"
 #include "node_perf_common.h"
 #include "env.h"
 #include "base_object-inl.h"
diff --git a/src/node_perf_common.h b/src/node_perf_common.h
index 0053ebf6119744..1c4cf01c871ad3 100644
--- a/src/node_perf_common.h
+++ b/src/node_perf_common.h
@@ -4,6 +4,7 @@
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
 #include "node.h"
+#include "uv.h"
 #include "v8.h"
 
 #include <algorithm>
diff --git a/src/node_process_events.cc b/src/node_process_events.cc
index d9c87173abe317..ccc40b65753d3d 100644
--- a/src/node_process_events.cc
+++ b/src/node_process_events.cc
@@ -1,8 +1,8 @@
 #include <stdarg.h>
 
-#include "env.h"
-#include "node_internals.h"
+#include "env-inl.h"
 #include "node_process.h"
+#include "util.h"
 
 namespace node {
 using v8::Context;
diff --git a/src/node_stat_watcher.cc b/src/node_stat_watcher.cc
index 7cf06393bb7484..9564a0a2b32ad7 100644
--- a/src/node_stat_watcher.cc
+++ b/src/node_stat_watcher.cc
@@ -20,10 +20,10 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #include "node_stat_watcher.h"
-#include "node_internals.h"
 #include "async_wrap-inl.h"
 #include "env.h"
 #include "node_file.h"
+#include "util.h"
 
 #include <string.h>
 #include <stdlib.h>
diff --git a/src/node_types.cc b/src/node_types.cc
index 048c47493d3c26..a53bcba555448f 100644
--- a/src/node_types.cc
+++ b/src/node_types.cc
@@ -1,4 +1,5 @@
-#include "node_internals.h"
+#include "env-inl.h"
+#include "node.h"
 
 using v8::Context;
 using v8::FunctionCallbackInfo;
diff --git a/src/node_url.cc b/src/node_url.cc
index 1841f32aad787c..d7402c4d043430 100644
--- a/src/node_url.cc
+++ b/src/node_url.cc
@@ -2,7 +2,7 @@
 #include "base_object-inl.h"
 #include "node_errors.h"
 #include "node_i18n.h"
-#include "node_internals.h"
+#include "util.h"
 
 #include <string>
 #include <vector>
diff --git a/src/node_util.cc b/src/node_util.cc
index ba81d9d6e7f763..2a7d90cfe2b661 100644
--- a/src/node_util.cc
+++ b/src/node_util.cc
@@ -1,6 +1,6 @@
-#include "node_internals.h"
 #include "node_errors.h"
 #include "node_watchdog.h"
+#include "util.h"
 
 namespace node {
 namespace util {
diff --git a/src/node_v8.cc b/src/node_v8.cc
index c61f1e6600b992..8ed0e416702e0b 100644
--- a/src/node_v8.cc
+++ b/src/node_v8.cc
@@ -20,7 +20,6 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #include "node.h"
-#include "node_internals.h"
 #include "env-inl.h"
 #include "util-inl.h"
 #include "v8.h"
diff --git a/src/node_worker.cc b/src/node_worker.cc
index 30004957a47442..cb496005844e21 100644
--- a/src/node_worker.cc
+++ b/src/node_worker.cc
@@ -1,7 +1,6 @@
 #include "node_worker.h"
 #include "debug_utils.h"
 #include "node_errors.h"
-#include "node_internals.h"
 #include "node_buffer.h"
 #include "node_perf.h"
 #include "util.h"
diff --git a/src/node_zlib.cc b/src/node_zlib.cc
index 4c65ede612c0ae..639d7f87c5abe4 100644
--- a/src/node_zlib.cc
+++ b/src/node_zlib.cc
@@ -21,7 +21,6 @@
 
 #include "node.h"
 #include "node_buffer.h"
-#include "node_internals.h"
 
 #include "async_wrap-inl.h"
 #include "env-inl.h"
@@ -59,6 +58,19 @@ using v8::Value;
 
 namespace {
 
+// Fewer than 64 bytes per chunk is not recommended.
+// Technically it could work with as few as 8, but even 64 bytes
+// is low.  Usually a MB or more is best.
+#define Z_MIN_CHUNK 64
+#define Z_MAX_CHUNK std::numeric_limits<double>::infinity()
+#define Z_DEFAULT_CHUNK (16 * 1024)
+#define Z_MIN_MEMLEVEL 1
+#define Z_MAX_MEMLEVEL 9
+#define Z_DEFAULT_MEMLEVEL 8
+#define Z_MIN_LEVEL -1
+#define Z_MAX_LEVEL 9
+#define Z_DEFAULT_LEVEL Z_DEFAULT_COMPRESSION
+
 #define ZLIB_ERROR_CODES(V)      \
   V(Z_OK)                        \
   V(Z_STREAM_END)                \
diff --git a/src/pipe_wrap.cc b/src/pipe_wrap.cc
index 6259cbdd1918dd..8ad1e0f594aa26 100644
--- a/src/pipe_wrap.cc
+++ b/src/pipe_wrap.cc
@@ -27,7 +27,6 @@
 #include "handle_wrap.h"
 #include "node.h"
 #include "node_buffer.h"
-#include "node_internals.h"
 #include "connect_wrap.h"
 #include "stream_base-inl.h"
 #include "stream_wrap.h"
diff --git a/src/process_wrap.cc b/src/process_wrap.cc
index d0514d64e08ffc..37afaf8ff961c9 100644
--- a/src/process_wrap.cc
+++ b/src/process_wrap.cc
@@ -20,7 +20,6 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #include "env-inl.h"
-#include "node_internals.h"
 #include "stream_base-inl.h"
 #include "stream_wrap.h"
 #include "util-inl.h"
diff --git a/src/spawn_sync.cc b/src/spawn_sync.cc
index eb16719b0517ee..5a600d2e21099c 100644
--- a/src/spawn_sync.cc
+++ b/src/spawn_sync.cc
@@ -22,8 +22,8 @@
 #include "spawn_sync.h"
 #include "debug_utils.h"
 #include "env-inl.h"
+#include "node_internals.h"
 #include "string_bytes.h"
-#include "util.h"
 
 #include <string.h>
 
diff --git a/src/spawn_sync.h b/src/spawn_sync.h
index 53fdee11d5a7e3..0ed6b9dff3a663 100644
--- a/src/spawn_sync.h
+++ b/src/spawn_sync.h
@@ -24,8 +24,9 @@
 
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
-#include "node_internals.h"
 #include "node_buffer.h"
+#include "uv.h"
+#include "v8.h"
 
 namespace node {
 
diff --git a/src/stream_base.cc b/src/stream_base.cc
index 739964eb85a762..a55cb60cfc5338 100644
--- a/src/stream_base.cc
+++ b/src/stream_base.cc
@@ -4,11 +4,9 @@
 #include "node.h"
 #include "node_buffer.h"
 #include "node_errors.h"
-#include "node_internals.h"
 #include "env-inl.h"
 #include "js_stream.h"
 #include "string_bytes.h"
-#include "util.h"
 #include "util-inl.h"
 #include "v8.h"
 
diff --git a/src/stream_pipe.cc b/src/stream_pipe.cc
index 931972a48c3a57..e58aa929e4b30e 100644
--- a/src/stream_pipe.cc
+++ b/src/stream_pipe.cc
@@ -1,7 +1,6 @@
 #include "stream_pipe.h"
 #include "stream_base-inl.h"
 #include "node_buffer.h"
-#include "node_internals.h"
 
 using v8::Context;
 using v8::External;
diff --git a/src/string_bytes.cc b/src/string_bytes.cc
index e4c4c0a7dbb34c..53bb95d80dab12 100644
--- a/src/string_bytes.cc
+++ b/src/string_bytes.cc
@@ -22,9 +22,10 @@
 #include "string_bytes.h"
 
 #include "base64.h"
-#include "node_internals.h"
-#include "node_errors.h"
+#include "env-inl.h"
 #include "node_buffer.h"
+#include "node_errors.h"
+#include "util.h"
 
 #include <limits.h>
 #include <string.h>  // memcpy
diff --git a/src/string_decoder.cc b/src/string_decoder.cc
index ceee1c9d762060..9cf1bd671b3fc9 100644
--- a/src/string_decoder.cc
+++ b/src/string_decoder.cc
@@ -1,7 +1,7 @@
-#include "string_decoder-inl.h"
-#include "string_bytes.h"
-#include "node_internals.h"
+#include "env-inl.h"
 #include "node_buffer.h"
+#include "string_bytes.h"
+#include "string_decoder-inl.h"
 
 using v8::Array;
 using v8::Context;
diff --git a/src/string_search.h b/src/string_search.h
index c924908b8b6573..95c746ea89e01e 100644
--- a/src/string_search.h
+++ b/src/string_search.h
@@ -7,7 +7,8 @@
 
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
-#include "node_internals.h"
+#include "util.h"
+
 #include <string.h>
 #include <algorithm>
 
diff --git a/src/timers.cc b/src/timers.cc
index f0ee1db4152501..f80e9e6be4d20c 100644
--- a/src/timers.cc
+++ b/src/timers.cc
@@ -1,4 +1,6 @@
-#include "node_internals.h"
+#include "env-inl.h"
+#include "util.h"
+#include "v8.h"
 
 #include <stdint.h>
 
diff --git a/src/tls_wrap.cc b/src/tls_wrap.cc
index b5d6559355cb87..d9f916f3d16a23 100644
--- a/src/tls_wrap.cc
+++ b/src/tls_wrap.cc
@@ -26,7 +26,6 @@
 #include "node_crypto_bio.h"  // NodeBIO
 // ClientHelloParser
 #include "node_crypto_clienthello-inl.h"
-#include "node_internals.h"
 #include "stream_base-inl.h"
 #include "util-inl.h"
 
diff --git a/src/tracing/traced_value.h b/src/tracing/traced_value.h
index 84e24c952528f5..7507978408f6ab 100644
--- a/src/tracing/traced_value.h
+++ b/src/tracing/traced_value.h
@@ -5,7 +5,8 @@
 #ifndef SRC_TRACING_TRACED_VALUE_H_
 #define SRC_TRACING_TRACED_VALUE_H_
 
-#include "node_internals.h"
+#include "node.h"
+#include "util.h"
 #include "v8.h"
 
 #include <stddef.h>
diff --git a/src/udp_wrap.cc b/src/udp_wrap.cc
index 2e076e26b9fbed..d838ef6e725b96 100644
--- a/src/udp_wrap.cc
+++ b/src/udp_wrap.cc
@@ -22,7 +22,6 @@
 #include "udp_wrap.h"
 #include "env-inl.h"
 #include "node_buffer.h"
-#include "node_internals.h"
 #include "handle_wrap.h"
 #include "req_wrap-inl.h"
 #include "util-inl.h"
diff --git a/src/util.h b/src/util.h
index 2fa16cadeac462..ea705b800bdf17 100644
--- a/src/util.h
+++ b/src/util.h
@@ -570,6 +570,94 @@ inline v8::MaybeLocal<v8::Value> ToV8Value(v8::Local<v8::Context> context,
 #define READONLY_STRING_PROPERTY(obj, name, str)                               \
   READONLY_PROPERTY(obj, name, ToV8Value(context, str).ToLocalChecked())
 
+// Variation on NODE_DEFINE_CONSTANT that sets a String value.
+#define NODE_DEFINE_STRING_CONSTANT(target, name, constant)                    \
+  do {                                                                         \
+    v8::Isolate* isolate = target->GetIsolate();                               \
+    v8::Local<v8::String> constant_name =                                      \
+        v8::String::NewFromUtf8(isolate, name, v8::NewStringType::kNormal)     \
+            .ToLocalChecked();                                                 \
+    v8::Local<v8::String> constant_value =                                     \
+        v8::String::NewFromUtf8(isolate, constant, v8::NewStringType::kNormal) \
+            .ToLocalChecked();                                                 \
+    v8::PropertyAttribute constant_attributes =                                \
+        static_cast<v8::PropertyAttribute>(v8::ReadOnly | v8::DontDelete);     \
+    target                                                                     \
+        ->DefineOwnProperty(isolate->GetCurrentContext(),                      \
+                            constant_name,                                     \
+                            constant_value,                                    \
+                            constant_attributes)                               \
+        .FromJust();                                                           \
+  } while (0)
+
+enum Endianness {
+  kLittleEndian,  // _Not_ LITTLE_ENDIAN, clashes with endian.h.
+  kBigEndian
+};
+
+inline enum Endianness GetEndianness() {
+  // Constant-folded by the compiler.
+  const union {
+    uint8_t u8[2];
+    uint16_t u16;
+  } u = {{1, 0}};
+  return u.u16 == 1 ? kLittleEndian : kBigEndian;
+}
+
+inline bool IsLittleEndian() {
+  return GetEndianness() == kLittleEndian;
+}
+
+inline bool IsBigEndian() {
+  return GetEndianness() == kBigEndian;
+}
+
+template <typename T, size_t N>
+constexpr size_t arraysize(const T (&)[N]) {
+  return N;
+}
+
+#ifndef ROUND_UP
+#define ROUND_UP(a, b) ((a) % (b) ? ((a) + (b)) - ((a) % (b)) : (a))
+#endif
+
+#ifdef __GNUC__
+#define MUST_USE_RESULT __attribute__((warn_unused_result))
+#else
+#define MUST_USE_RESULT
+#endif
+
+class SlicedArguments {
+ public:
+  inline explicit SlicedArguments(
+      const v8::FunctionCallbackInfo<v8::Value>& args, size_t start = 0);
+  inline size_t size() const { return size_; }
+  inline v8::Local<v8::Value>* data() { return data_; }
+
+ private:
+  size_t size_;
+  v8::Local<v8::Value>* data_;
+  v8::Local<v8::Value> fixed_[64];
+  std::vector<v8::Local<v8::Value>> dynamic_;
+};
+
+SlicedArguments::SlicedArguments(
+    const v8::FunctionCallbackInfo<v8::Value>& args, size_t start)
+    : size_(0), data_(fixed_) {
+  const size_t length = static_cast<size_t>(args.Length());
+  if (start >= length) return;
+  const size_t size = length - start;
+
+  if (size > arraysize(fixed_)) {
+    dynamic_.resize(size);
+    data_ = dynamic_.data();
+  }
+
+  for (size_t i = 0; i < size; ++i) data_[i] = args[i + start];
+
+  size_ = size;
+}
+
 }  // namespace node
 
 #endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
diff --git a/src/uv.cc b/src/uv.cc
index 5422b0d2403d39..59469fc3075a52 100644
--- a/src/uv.cc
+++ b/src/uv.cc
@@ -22,8 +22,8 @@
 #include "uv.h"
 #include "env-inl.h"
 #include "node.h"
-#include "node_internals.h"
 #include "node_process.h"
+#include "util.h"
 
 namespace node {