feat: implement output.clean.keep: Option<string>

crates/node_binding/binding.d.ts

@@ -518,6 +518,17 @@ export interface JsChunkGroupOrigin {
   request?: string
 }
 
+/**
+ * File clean options
+ *
+ * This matches with:
+ * - keep:
+ *   - If a string, keep the files under this path
+ */
+export interface JsCleanOptions {
+  keep?: string
+}
+
 export interface JsCodegenerationResult {
   sources: Record<string, string>
 }
@@ -1744,7 +1755,7 @@ export interface RawOptions {
 export interface RawOutputOptions {
   path: string
   pathinfo: boolean | "verbose"
-  clean: boolean
+  clean: boolean | JsCleanOptions
   publicPath: "auto" | JsFilename
   assetModuleFilename: JsFilename
   wasmLoading: string

crates/rspack_binding_options/src/options/raw_output.rs

@@ -1,8 +1,8 @@
 use napi::Either;
 use napi_derive::napi;
 use rspack_binding_values::library::JsLibraryOptions;
-use rspack_binding_values::JsFilename;
-use rspack_core::{CrossOriginLoading, Environment, PathInfo};
+use rspack_binding_values::{JsCleanOptions, JsFilename};
+use rspack_core::{CleanOptions, CrossOriginLoading, Environment, PathInfo};
 use rspack_core::{OutputOptions, TrustedTypes};
 
 #[derive(Debug)]
@@ -66,7 +66,7 @@ pub struct RawOutputOptions {
   pub path: String,
   #[napi(ts_type = "boolean | \"verbose\"")]
   pub pathinfo: Either<bool, String>,
-  pub clean: bool,
+  pub clean: Either<bool, JsCleanOptions>,
   #[napi(ts_type = "\"auto\" | JsFilename")]
   pub public_path: JsFilename,
   pub asset_module_filename: JsFilename,
@@ -120,10 +120,15 @@ impl TryFrom<RawOutputOptions> for OutputOptions {
       Either::B(s) => PathInfo::String(s),
     };
 
+    let clean = match value.clean {
+      Either::A(b) => CleanOptions::CleanAll(b),
+      Either::B(cop) => cop.to_clean_options(),
+    };
+
     Ok(OutputOptions {
       path: value.path.into(),
       pathinfo,
-      clean: value.clean,
+      clean,
       public_path: value.public_path.into(),
       asset_module_filename: value.asset_module_filename.into(),
       wasm_loading: value.wasm_loading.as_str().into(),

crates/rspack_binding_values/src/clean_options.rs

@@ -0,0 +1,31 @@
+use napi_derive::napi;
+use rspack_core::CleanOptions;
+use rspack_napi::napi;
+
+/// File clean options
+///
+/// This matches with:
+/// - keep:
+///   - If a string, keep the files under this path
+#[napi(object, object_to_js = false)]
+#[derive(Debug)]
+pub struct JsCleanOptions {
+  pub keep: Option<String>,
+  // todo:
+  // - support RegExp type
+  //   if path match the RegExp, keep the file
+  // - support function type
+  //    if the fn returns true on path str, keep the file
+}
+
+impl JsCleanOptions {
+  pub fn to_clean_options(&self) -> CleanOptions {
+    let keep = self.keep.as_ref();
+    if let Some(path) = keep {
+      let p = path.as_str();
+      CleanOptions::from(p)
+    } else {
+      CleanOptions::CleanAll(false)
+    }
+  }
+}

crates/rspack_binding_values/src/lib.rs

@@ -4,6 +4,7 @@ mod asset_condition;
 mod chunk;
 mod chunk_graph;
 mod chunk_group;
+mod clean_options;
 mod codegen_result;
 mod compilation;
 mod context_module_factory;
@@ -30,6 +31,7 @@ pub use asset_condition::*;
 pub use chunk::*;
 pub use chunk_graph::*;
 pub use chunk_group::*;
+pub use clean_options::*;
 pub use codegen_result::*;
 pub use compilation::*;
 pub use context_module_factory::*;

crates/rspack_core/src/compiler/mod.rs

@@ -20,8 +20,8 @@ use crate::cache::{new_cache, Cache};
 use crate::incremental::IncrementalPasses;
 use crate::old_cache::Cache as OldCache;
 use crate::{
-  fast_set, include_hash, BoxPlugin, CompilerOptions, Logger, PluginDriver, ResolverFactory,
-  SharedPluginDriver,
+  fast_set, include_hash, trim_dir, BoxPlugin, CleanOptions, CompilerOptions, Logger, PluginDriver,
+  ResolverFactory, SharedPluginDriver,
 };
 use crate::{ContextModuleFactory, NormalModuleFactory};
 
@@ -73,7 +73,7 @@ impl Compiler {
     options: CompilerOptions,
     plugins: Vec<BoxPlugin>,
     buildtime_plugins: Vec<BoxPlugin>,
-    output_filesystem: Option<Box<dyn WritableFileSystem + Send + Sync>>,
+    output_filesystem: Option<Box<dyn WritableFileSystem>>,
     // only supports passing input_filesystem in rust api, no support for js api
     input_filesystem: Option<Arc<dyn FileSystem + Send + Sync>>,
     // no need to pass resolve_factory in rust api
@@ -264,32 +264,7 @@ impl Compiler {
 
   #[instrument(name = "emit_assets", skip_all)]
   pub async fn emit_assets(&mut self) -> Result<()> {
-    if self.options.output.clean {
-      if self.emitted_asset_versions.is_empty() {
-        self
-          .output_filesystem
-          .remove_dir_all(&self.options.output.path)
-          .await?;
-      } else {
-        // clean unused file
-        let assets = self.compilation.assets();
-        let _ = self
-          .emitted_asset_versions
-          .iter()
-          .filter_map(|(filename, _version)| {
-            if !assets.contains_key(filename) {
-              let filename = filename.to_owned();
-              Some(async {
-                let filename = Utf8Path::new(&self.options.output.path).join(filename);
-                let _ = self.output_filesystem.remove_file(&filename).await;
-              })
-            } else {
-              None
-            }
-          })
-          .collect::<FuturesResults<_>>();
-      }
-    }
+    self.run_clean_options().await?;
 
     self
       .plugin_driver
@@ -421,6 +396,58 @@ impl Compiler {
     Ok(())
   }
 
+  async fn run_clean_options(&mut self) -> Result<()> {
+    let clean_options = &self.options.output.clean;
+
+    // keep all
+    if let CleanOptions::CleanAll(false) = clean_options {
+      return Ok(());
+    }
+
+    if self.emitted_asset_versions.is_empty() {
+      if let CleanOptions::KeepPath(p) = clean_options {
+        let path_to_keep = self.options.output.path.join(Utf8Path::new(p));
+        trim_dir(
+          &*self.output_filesystem,
+          &self.options.output.path,
+          &path_to_keep,
+        )
+        .await?;
+        return Ok(());
+      }
+
+      // CleanOptions::CleanAll(true) only
+      debug_assert!(matches!(clean_options, CleanOptions::CleanAll(true)));
+
+      self
+        .output_filesystem
+        .remove_dir_all(&self.options.output.path)
+        .await?;
+      return Ok(());
+    }
+
+    let assets = self.compilation.assets();
+    let _ = self
+      .emitted_asset_versions
+      .iter()
+      .filter_map(|(filename, _version)| {
+        if !assets.contains_key(filename) {
+          let filename = filename.to_owned();
+          Some(async {
+            if !clean_options.keep(filename.as_str()) {
+              let filename = Utf8Path::new(&self.options.output.path).join(filename);
+              let _ = self.output_filesystem.remove_file(&filename).await;
+            }
+          })
+        } else {
+          None
+        }
+      })
+      .collect::<FuturesResults<_>>();
+
+    Ok(())
+  }
+
   fn new_compilation_params(&self) -> CompilationParams {
     CompilationParams {
       normal_module_factory: Arc::new(NormalModuleFactory::new(

crates/rspack_core/src/options/clean_options.rs

@@ -0,0 +1,51 @@
+use std::{path::PathBuf, str::FromStr};
+
+use rspack_paths::Utf8PathBuf;
+
+/// rust representation of the clean options
+// TODO: support RegExp and function type
+#[derive(Debug)]
+pub enum CleanOptions {
+  // if true, clean all files
+  CleanAll(bool),
+  // keep the files under this path
+  KeepPath(Utf8PathBuf),
+}
+
+impl CleanOptions {
+  pub fn keep(&self, path: &str) -> bool {
+    match self {
+      Self::CleanAll(value) => !*value,
+      Self::KeepPath(value) => {
+        let path = PathBuf::from(path);
+        path.starts_with(value)
+      }
+    }
+  }
+}
+
+impl From<bool> for CleanOptions {
+  fn from(value: bool) -> Self {
+    Self::CleanAll(value)
+  }
+}
+
+impl From<&'_ str> for CleanOptions {
+  fn from(value: &str) -> Self {
+    let pb = Utf8PathBuf::from_str(value).expect("should be a valid path");
+    Self::KeepPath(pb)
+  }
+}
+impl From<&String> for CleanOptions {
+  fn from(value: &String) -> Self {
+    let pb = Utf8PathBuf::from_str(value).expect("should be a valid path");
+    Self::KeepPath(pb)
+  }
+}
+
+impl From<String> for CleanOptions {
+  fn from(value: String) -> Self {
+    let pb = Utf8PathBuf::from_str(&value).expect("should be a valid path");
+    Self::KeepPath(pb)
+  }
+}

crates/rspack_core/src/options/mod.rs

@@ -31,3 +31,5 @@ mod node;
 pub use node::*;
 mod filename;
 pub use filename::*;
+mod clean_options;
+pub use clean_options::*;

crates/rspack_core/src/options/output.rs

@@ -9,6 +9,7 @@ use rspack_macros::MergeFrom;
 use rspack_paths::{AssertUtf8, Utf8Path, Utf8PathBuf};
 use sugar_path::SugarPath;
 
+use super::CleanOptions;
 use crate::{Chunk, ChunkGroupByUkey, ChunkKind, Compilation, Filename, FilenameTemplate};
 
 #[derive(Debug)]
@@ -21,7 +22,7 @@ pub enum PathInfo {
 pub struct OutputOptions {
   pub path: Utf8PathBuf,
   pub pathinfo: PathInfo,
-  pub clean: bool,
+  pub clean: CleanOptions,
   pub public_path: PublicPath,
   pub asset_module_filename: Filename,
   pub wasm_loading: WasmLoading,