diff --git a/nix-js/benches/basic_ops.rs b/nix-js/benches/basic_ops.rs
index 155479d..4a1b170 100644
--- a/nix-js/benches/basic_ops.rs
+++ b/nix-js/benches/basic_ops.rs
@@ -1,7 +1,8 @@
 mod utils;
 
-use criterion::{Criterion, criterion_group, criterion_main};
 use std::hint::black_box;
+
+use criterion::{Criterion, criterion_group, criterion_main};
 use utils::eval;
 
 fn bench_arithmetic(c: &mut Criterion) {
diff --git a/nix-js/benches/builtins.rs b/nix-js/benches/builtins.rs
index 9e29907..5e6e7ef 100644
--- a/nix-js/benches/builtins.rs
+++ b/nix-js/benches/builtins.rs
@@ -1,7 +1,8 @@
 mod utils;
 
-use criterion::{Criterion, criterion_group, criterion_main};
 use std::hint::black_box;
+
+use criterion::{Criterion, criterion_group, criterion_main};
 use utils::eval;
 
 fn bench_builtin_math(c: &mut Criterion) {
diff --git a/nix-js/benches/compile_time.rs b/nix-js/benches/compile_time.rs
index d4e6436..fbfec20 100644
--- a/nix-js/benches/compile_time.rs
+++ b/nix-js/benches/compile_time.rs
@@ -1,8 +1,9 @@
 mod utils;
 
+use std::hint::black_box;
+
 use criterion::{Criterion, criterion_group, criterion_main};
 use nix_js::context::Context;
-use std::hint::black_box;
 use utils::compile;
 
 fn bench_parse_and_downgrade(c: &mut Criterion) {
diff --git a/nix-js/benches/thunk_scope.rs b/nix-js/benches/thunk_scope.rs
index c90473e..d71e3ad 100644
--- a/nix-js/benches/thunk_scope.rs
+++ b/nix-js/benches/thunk_scope.rs
@@ -1,7 +1,8 @@
 mod utils;
 
-use criterion::{Criterion, criterion_group, criterion_main};
 use std::hint::black_box;
+
+use criterion::{Criterion, criterion_group, criterion_main};
 use utils::eval;
 
 fn bench_non_recursive(c: &mut Criterion) {
diff --git a/nix-js/src/context.rs b/nix-js/src/context.rs
index 447c686..5d97c45 100644
--- a/nix-js/src/context.rs
+++ b/nix-js/src/context.rs
@@ -8,7 +8,7 @@ use hashbrown::{DefaultHashBuilder, HashMap, HashSet, HashTable};
 use rnix::TextRange;
 use string_interner::DefaultStringInterner;
 
-use crate::bytecode::{self, BytecodeContext, Bytecode, Constant};
+use crate::bytecode::{self, Bytecode, BytecodeContext, Constant};
 use crate::codegen::{CodegenContext, compile};
 use crate::disassembler::{Disassembler, DisassemblerContext};
 use crate::downgrade::*;
@@ -383,11 +383,7 @@ impl Ctx {
         Ok(bytecode)
     }
 
-    fn compile_bytecode_scoped(
-        &mut self,
-        source: Source,
-        scope: Vec<String>,
-    ) -> Result<Bytecode> {
+    fn compile_bytecode_scoped(&mut self, source: Source, scope: Vec<String>) -> Result<Bytecode> {
         let scope = Scope::ScopedImport(
             scope
                 .into_iter()
@@ -477,11 +473,7 @@ impl RuntimeContext for Ctx {
     fn compile_bytecode(&mut self, source: Source) -> Result<Bytecode> {
         self.compile_bytecode(source)
     }
-    fn compile_bytecode_scoped(
-        &mut self,
-        source: Source,
-        scope: Vec<String>,
-    ) -> Result<Bytecode> {
+    fn compile_bytecode_scoped(&mut self, source: Source, scope: Vec<String>) -> Result<Bytecode> {
         self.compile_bytecode_scoped(source, scope)
     }
     fn get_source(&self, id: usize) -> Source {
@@ -494,11 +486,11 @@ impl RuntimeContext for Ctx {
         let spans = unsafe { &*self.spans.get() };
         spans[id]
     }
-    fn take_unsynced(&mut self) -> (Vec<String>, Vec<Constant>, usize, usize) {
+    fn get_unsynced(&mut self) -> (&[String], &[Constant], usize, usize) {
         let strings_base = self.synced_strings;
         let constants_base = self.synced_constants;
-        let new_strings = self.global_strings[strings_base..].to_vec();
-        let new_constants = self.global_constants[constants_base..].to_vec();
+        let new_strings = &self.global_strings[strings_base..];
+        let new_constants = &self.global_constants[constants_base..];
         self.synced_strings = self.global_strings.len();
         self.synced_constants = self.global_constants.len();
         (new_strings, new_constants, strings_base, constants_base)
@@ -507,10 +499,14 @@ impl RuntimeContext for Ctx {
 
 impl DisassemblerContext for Ctx {
     fn lookup_string(&self, id: u32) -> &str {
-        self.global_strings.get(id as usize).expect("string not found")
+        self.global_strings
+            .get(id as usize)
+            .expect("string not found")
     }
     fn lookup_constant(&self, id: u32) -> &Constant {
-        self.global_constants.get(id as usize).expect("constant not found")
+        self.global_constants
+            .get(id as usize)
+            .expect("constant not found")
     }
 }
 
diff --git a/nix-js/src/downgrade.rs b/nix-js/src/downgrade.rs
index 6bc8477..c69feec 100644
--- a/nix-js/src/downgrade.rs
+++ b/nix-js/src/downgrade.rs
@@ -25,8 +25,8 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>, T> Require<'id, 'ir, Ctx, T
     }
 }
 
-impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>, T, E: std::fmt::Display> Require<'id, 'ir, Ctx, T>
-    for std::result::Result<T, E>
+impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>, T, E: std::fmt::Display>
+    Require<'id, 'ir, Ctx, T> for std::result::Result<T, E>
 {
     #[inline]
     fn require(self, ctx: &Ctx, span: TextRange) -> Result<T> {
diff --git a/nix-js/src/fetcher/download.rs b/nix-js/src/fetcher/download.rs
index 2295dc9..7fad254 100644
--- a/nix-js/src/fetcher/download.rs
+++ b/nix-js/src/fetcher/download.rs
@@ -1,6 +1,7 @@
-use reqwest::blocking::Client;
 use std::time::Duration;
 
+use reqwest::blocking::Client;
+
 pub struct Downloader {
     client: Client,
 }
diff --git a/nix-js/src/fetcher/metadata_cache.rs b/nix-js/src/fetcher/metadata_cache.rs
index 39180aa..dc8592f 100644
--- a/nix-js/src/fetcher/metadata_cache.rs
+++ b/nix-js/src/fetcher/metadata_cache.rs
@@ -1,9 +1,10 @@
 #![allow(dead_code)]
 
+use std::path::PathBuf;
+use std::time::{SystemTime, UNIX_EPOCH};
+
 use rusqlite::{Connection, OptionalExtension, params};
 use serde::{Deserialize, Serialize};
-use std::path::PathBuf;
-use std::time::{SystemTime, UNIX_EPOCH};
 
 #[derive(Debug)]
 pub enum CacheError {
diff --git a/nix-js/src/logging.rs b/nix-js/src/logging.rs
index 78b147c..7110edb 100644
--- a/nix-js/src/logging.rs
+++ b/nix-js/src/logging.rs
@@ -1,5 +1,6 @@
 use std::env;
 use std::io::IsTerminal;
+
 use tracing_subscriber::{EnvFilter, Layer, fmt, layer::SubscriberExt, util::SubscriberInitExt};
 
 pub fn init_logging() {
diff --git a/nix-js/src/nar.rs b/nix-js/src/nar.rs
index 4e38910..77b3579 100644
--- a/nix-js/src/nar.rs
+++ b/nix-js/src/nar.rs
@@ -1,8 +1,9 @@
-use nix_nar::Encoder;
-use sha2::{Digest, Sha256};
 use std::io::Read;
 use std::path::Path;
 
+use nix_nar::Encoder;
+use sha2::{Digest, Sha256};
+
 use crate::error::{Error, Result};
 
 pub fn compute_nar_hash(path: &Path) -> Result<[u8; 32]> {
@@ -27,10 +28,12 @@ pub fn pack_nar(path: &Path) -> Result<Vec<u8>> {
 #[cfg(test)]
 #[allow(clippy::unwrap_used)]
 mod tests {
-    use super::*;
     use std::fs;
+
     use tempfile::TempDir;
 
+    use super::*;
+
     #[test_log::test]
     fn test_simple_file() {
         let temp = TempDir::new().unwrap();
diff --git a/nix-js/src/runtime.rs b/nix-js/src/runtime.rs
index 7a878e9..f45227c 100644
--- a/nix-js/src/runtime.rs
+++ b/nix-js/src/runtime.rs
@@ -26,15 +26,11 @@ pub(crate) trait RuntimeContext: 'static {
     fn compile(&mut self, source: Source) -> Result<String>;
     fn compile_scoped(&mut self, source: Source, scope: Vec<String>) -> Result<String>;
     fn compile_bytecode(&mut self, source: Source) -> Result<Bytecode>;
-    fn compile_bytecode_scoped(
-        &mut self,
-        source: Source,
-        scope: Vec<String>,
-    ) -> Result<Bytecode>;
+    fn compile_bytecode_scoped(&mut self, source: Source, scope: Vec<String>) -> Result<Bytecode>;
     fn get_source(&self, id: usize) -> Source;
     fn get_store(&self) -> &DaemonStore;
     fn get_span(&self, id: usize) -> (usize, rnix::TextRange);
-    fn take_unsynced(&mut self) -> (Vec<String>, Vec<Constant>, usize, usize);
+    fn get_unsynced(&mut self) -> (&[String], &[Constant], usize, usize);
 }
 
 pub(crate) trait OpStateExt<Ctx: RuntimeContext> {
@@ -465,7 +461,7 @@ fn sync_global_tables<Ctx: RuntimeContext>(
     cached: &CachedFunctions,
     ctx: &mut Ctx,
 ) {
-    let (new_strings, new_constants, strings_base, constants_base) = ctx.take_unsynced();
+    let (new_strings, new_constants, strings_base, constants_base) = ctx.get_unsynced();
 
     if !new_strings.is_empty() {
         let s_array = v8::Local::new(scope, &cached.strings_array);
diff --git a/nix-js/src/runtime/inspector.rs b/nix-js/src/runtime/inspector.rs
index 3ab8ba9..781278f 100644
--- a/nix-js/src/runtime/inspector.rs
+++ b/nix-js/src/runtime/inspector.rs
@@ -2,6 +2,14 @@
 
 // Alias for the future `!` type.
 use core::convert::Infallible as Never;
+use std::cell::RefCell;
+use std::net::SocketAddr;
+use std::pin::pin;
+use std::process;
+use std::rc::Rc;
+use std::task::Poll;
+use std::thread;
+
 use deno_core::InspectorMsg;
 use deno_core::InspectorSessionChannels;
 use deno_core::InspectorSessionKind;
@@ -24,13 +32,6 @@ use fastwebsockets::WebSocket;
 use hashbrown::HashMap;
 use hyper::body::Bytes;
 use hyper_util::rt::TokioIo;
-use std::cell::RefCell;
-use std::net::SocketAddr;
-use std::pin::pin;
-use std::process;
-use std::rc::Rc;
-use std::task::Poll;
-use std::thread;
 use tokio::net::TcpListener;
 use tokio::sync::broadcast;
 use uuid::Uuid;
diff --git a/nix-js/src/store/daemon.rs b/nix-js/src/store/daemon.rs
index eed6213..8ce4705 100644
--- a/nix-js/src/store/daemon.rs
+++ b/nix-js/src/store/daemon.rs
@@ -87,11 +87,12 @@ impl Store for DaemonStore {
         recursive: bool,
         references: Vec<String>,
     ) -> Result<String> {
+        use std::fs;
+
         use nix_compat::nix_daemon::types::AddToStoreNarRequest;
         use nix_compat::nixhash::{CAHash, NixHash};
         use nix_compat::store_path::{StorePath, build_ca_path};
         use sha2::{Digest, Sha256};
-        use std::fs;
         use tempfile::NamedTempFile;
 
         let temp_file = NamedTempFile::new()
@@ -237,11 +238,12 @@ impl Store for DaemonStore {
         content: &str,
         references: Vec<String>,
     ) -> Result<String> {
+        use std::fs;
+
         use nix_compat::nix_daemon::types::AddToStoreNarRequest;
         use nix_compat::nixhash::CAHash;
         use nix_compat::store_path::{StorePath, build_text_path};
         use sha2::{Digest, Sha256};
-        use std::fs;
         use tempfile::NamedTempFile;
 
         let temp_file = NamedTempFile::new()
diff --git a/nix-js/src/value.rs b/nix-js/src/value.rs
index 8161084..49fa388 100644
--- a/nix-js/src/value.rs
+++ b/nix-js/src/value.rs
@@ -1,7 +1,6 @@
 use core::fmt::{Debug, Display, Formatter, Result as FmtResult};
 use core::hash::Hash;
 use core::ops::Deref;
-
 use std::borrow::Cow;
 use std::collections::BTreeMap;
 use std::ops::DerefMut;
diff --git a/nix-js/tests/tests/basic_eval.rs b/nix-js/tests/tests/basic_eval.rs
index 828ab50..6a00e44 100644
--- a/nix-js/tests/tests/basic_eval.rs
+++ b/nix-js/tests/tests/basic_eval.rs
@@ -1,6 +1,7 @@
-use crate::utils::{eval, eval_result};
 use nix_js::value::Value;
 
+use crate::utils::{eval, eval_result};
+
 #[test_log::test]
 fn arithmetic() {
     assert_eq!(eval("1 + 1"), Value::Int(2));
diff --git a/nix-js/tests/tests/builtins.rs b/nix-js/tests/tests/builtins.rs
index c18dedb..6cd944b 100644
--- a/nix-js/tests/tests/builtins.rs
+++ b/nix-js/tests/tests/builtins.rs
@@ -1,7 +1,9 @@
-use crate::utils::eval;
-use nix_js::value::{AttrSet, List, Value};
 use std::collections::BTreeMap;
 
+use nix_js::value::{AttrSet, List, Value};
+
+use crate::utils::eval;
+
 #[test_log::test]
 fn builtins_accessible() {
     let result = eval("builtins");
diff --git a/nix-js/tests/tests/builtins_store.rs b/nix-js/tests/tests/builtins_store.rs
index 58127e1..1c21414 100644
--- a/nix-js/tests/tests/builtins_store.rs
+++ b/nix-js/tests/tests/builtins_store.rs
@@ -1,6 +1,7 @@
-use crate::utils::eval_result;
 use nix_js::value::Value;
 
+use crate::utils::eval_result;
+
 #[test_log::test]
 fn to_file_simple() {
     let result =
diff --git a/nix-js/tests/tests/derivation.rs b/nix-js/tests/tests/derivation.rs
index 5509622..5eb2937 100644
--- a/nix-js/tests/tests/derivation.rs
+++ b/nix-js/tests/tests/derivation.rs
@@ -1,6 +1,7 @@
-use crate::utils::{eval_deep, eval_deep_result};
 use nix_js::value::Value;
 
+use crate::utils::{eval_deep, eval_deep_result};
+
 #[test_log::test]
 fn add_operator_preserves_derivation_context() {
     let result = eval_deep(
diff --git a/nix-js/tests/tests/free_globals.rs b/nix-js/tests/tests/free_globals.rs
index 8e23396..6f7b13e 100644
--- a/nix-js/tests/tests/free_globals.rs
+++ b/nix-js/tests/tests/free_globals.rs
@@ -1,6 +1,7 @@
-use crate::utils::{eval, eval_result};
 use nix_js::value::{List, Value};
 
+use crate::utils::{eval, eval_result};
+
 #[test_log::test]
 fn true_literal() {
     assert_eq!(eval("true"), Value::Bool(true));
diff --git a/nix-js/tests/tests/functions.rs b/nix-js/tests/tests/functions.rs
index b3a06b1..5bf9199 100644
--- a/nix-js/tests/tests/functions.rs
+++ b/nix-js/tests/tests/functions.rs
@@ -1,6 +1,7 @@
-use crate::utils::{eval, eval_result};
 use nix_js::value::Value;
 
+use crate::utils::{eval, eval_result};
+
 #[test_log::test]
 fn required_parameters() {
     assert_eq!(eval("({ a, b }: a + b) { a = 1; b = 2; }"), Value::Int(3));
diff --git a/nix-js/tests/tests/io_operations.rs b/nix-js/tests/tests/io_operations.rs
index dd85770..a22e4c5 100644
--- a/nix-js/tests/tests/io_operations.rs
+++ b/nix-js/tests/tests/io_operations.rs
@@ -1,8 +1,9 @@
-use crate::utils::{eval, eval_result};
 use nix_js::context::Context;
 use nix_js::error::Source;
 use nix_js::value::Value;
 
+use crate::utils::{eval, eval_result};
+
 #[test_log::test]
 fn import_absolute_path() {
     let temp_dir = tempfile::tempdir().unwrap();
diff --git a/nix-js/tests/tests/numeric_types.rs b/nix-js/tests/tests/numeric_types.rs
index 4b0c3f2..a0465e7 100644
--- a/nix-js/tests/tests/numeric_types.rs
+++ b/nix-js/tests/tests/numeric_types.rs
@@ -1,6 +1,7 @@
-use crate::utils::eval;
 use nix_js::value::Value;
 
+use crate::utils::eval;
+
 #[test_log::test]
 fn large_i64_max() {
     assert_eq!(eval("9223372036854775807"), Value::Int(9223372036854775807));
diff --git a/nix-js/tests/tests/operators.rs b/nix-js/tests/tests/operators.rs
index 7adddee..fb9d66d 100644
--- a/nix-js/tests/tests/operators.rs
+++ b/nix-js/tests/tests/operators.rs
@@ -1,7 +1,9 @@
-use crate::utils::eval;
-use nix_js::value::{AttrSet, List, Symbol, Value};
 use std::collections::BTreeMap;
 
+use nix_js::value::{AttrSet, List, Symbol, Value};
+
+use crate::utils::eval;
+
 #[test_log::test]
 fn addition() {
     assert_eq!(eval("1 + 1"), Value::Int(2));
diff --git a/nix-js/tests/tests/path_operations.rs b/nix-js/tests/tests/path_operations.rs
index 470843c..609d3f7 100644
--- a/nix-js/tests/tests/path_operations.rs
+++ b/nix-js/tests/tests/path_operations.rs
@@ -1,6 +1,7 @@
-use crate::utils::{eval, eval_result};
 use nix_js::value::Value;
 
+use crate::utils::{eval, eval_result};
+
 #[test_log::test]
 fn path_type_of() {
     let result = eval("builtins.typeOf ./foo");
diff --git a/nix-js/tests/tests/regex.rs b/nix-js/tests/tests/regex.rs
index 4c4f328..358346c 100644
--- a/nix-js/tests/tests/regex.rs
+++ b/nix-js/tests/tests/regex.rs
@@ -1,6 +1,6 @@
-use crate::utils::eval;
 use nix_js::value::{List, Value};
 
+use crate::utils::eval;
 use crate::utils::eval_result;
 
 #[test_log::test]
diff --git a/nix-js/tests/tests/string_context.rs b/nix-js/tests/tests/string_context.rs
index 4b0b0d8..85ed1d0 100644
--- a/nix-js/tests/tests/string_context.rs
+++ b/nix-js/tests/tests/string_context.rs
@@ -1,7 +1,8 @@
-use crate::utils::eval_result;
 use nix_js::context::Context;
 use nix_js::value::Value;
 
+use crate::utils::eval_result;
+
 fn eval(expr: &str) -> Value {
     eval_result(expr).unwrap_or_else(|e| panic!("{}", e))
 }
diff --git a/nix-js/tests/tests/thunk_scope.rs b/nix-js/tests/tests/thunk_scope.rs
index 0bdfbc3..dfc9f52 100644
--- a/nix-js/tests/tests/thunk_scope.rs
+++ b/nix-js/tests/tests/thunk_scope.rs
@@ -1,6 +1,7 @@
-use crate::utils::eval;
 use nix_js::value::Value;
 
+use crate::utils::eval;
+
 #[test_log::test]
 fn non_recursive_bindings() {
     assert_eq!(eval("let x = 1; y = 2; z = x + y; in z"), Value::Int(3));
diff --git a/nix-js/tests/tests/to_string.rs b/nix-js/tests/tests/to_string.rs
index 7614990..e1a27bb 100644
--- a/nix-js/tests/tests/to_string.rs
+++ b/nix-js/tests/tests/to_string.rs
@@ -1,6 +1,7 @@
-use crate::utils::{eval, eval_result};
 use nix_js::value::Value;
 
+use crate::utils::{eval, eval_result};
+
 #[test_log::test]
 fn string_returns_as_is() {
     assert_eq!(
diff --git a/rustfmt.toml b/rustfmt.toml
new file mode 100644
index 0000000..bf96e77
--- /dev/null
+++ b/rustfmt.toml
@@ -0,0 +1 @@
+group_imports = "StdExternalCrate"