biomejs · ematipico · Dec 5, 2025 · Nov 27, 2025 · Dec 5, 2025 · Dec 5, 2025
diff --git a/.changeset/tough-buckets-write.md b/.changeset/tough-buckets-write.md
@@ -0,0 +1,5 @@
+---
+"@biomejs/biome": patch
+---
+
+Improved the performance of the Biome Formatter by enabling the internal source maps only when needed.
diff --git a/crates/biome_css_semantic/src/format_semantic_model.rs b/crates/biome_css_semantic/src/format_semantic_model.rs
@@ -3,7 +3,7 @@ use biome_formatter::prelude::*;
 use biome_formatter::write;
 use biome_formatter::{
     FormatContext, FormatOptions, IndentStyle, IndentWidth, LineEnding, LineWidth,
-    TransformSourceMap,
+    SourceMapGeneration, TransformSourceMap,
 };
 use biome_rowan::{AstNode, TextSize};
 
@@ -33,6 +33,7 @@ impl FormatOptions for FormatSemanticModelOptions {
             print_width: self.line_width().into(),
             line_ending: self.line_ending(),
             indent_style: self.indent_style(),
+            source_map_generation: SourceMapGeneration::default(),
         }
     }
 }

diff --git a/crates/biome_formatter/src/format_element/document.rs b/crates/biome_formatter/src/format_element/document.rs
@@ -6,7 +6,8 @@ use crate::prelude::tag::GroupMode;
 use crate::prelude::*;
 use crate::{
     BufferExtensions, Format, FormatContext, FormatElement, FormatOptions, FormatResult, Formatter,
-    IndentStyle, IndentWidth, LineEnding, LineWidth, PrinterOptions, TransformSourceMap,
+    IndentStyle, IndentWidth, LineEnding, LineWidth, PrinterOptions, SourceMapGeneration,
+    TransformSourceMap,
 };
 use crate::{format, write};
 use biome_rowan::TextSize;
@@ -266,6 +267,7 @@ impl FormatOptions for IrFormatOptions {
             print_width: self.line_width().into(),
             line_ending: LineEnding::Lf,
             indent_style: IndentStyle::Space,
+            source_map_generation: SourceMapGeneration::default(),
         }
     }
 }

diff --git a/crates/biome_formatter/src/lib.rs b/crates/biome_formatter/src/lib.rs
@@ -74,6 +74,7 @@ pub use buffer::{
 pub use builders::BestFitting;
 pub use format_element::{FormatElement, LINE_TERMINATORS, normalize_newlines};
 pub use group_id::GroupId;
+pub use printer::SourceMapGeneration;
 pub use source_map::{TransformSourceMap, TransformSourceMapBuilder};
 use std::num::ParseIntError;
 use std::str::FromStr;
@@ -1021,8 +1022,16 @@ where
         Ok(printed)
     }
 
-    pub fn print_with_indent(&self, indent: u16) -> PrintResult<Printed> {
-        let print_options = self.context.options().as_print_options();
+    pub fn print_with_indent(
+        &self,
+        indent: u16,
+        source_map: SourceMapGeneration,
+    ) -> PrintResult<Printed> {
+        let print_options = self
+            .context
+            .options()
+            .as_print_options()
+            .with_source_map_generation(source_map);
         let printed = Printer::new(print_options).print_with_indent(&self.document, indent)?;
 
         let printed = match self.context.source_map() {
@@ -2045,7 +2054,7 @@ pub fn format_sub_tree<L: FormatLanguage>(
     };
 
     let formatted = format_node(root, language, false)?;
-    let mut printed = formatted.print_with_indent(initial_indent)?;
+    let mut printed = formatted.print_with_indent(initial_indent, SourceMapGeneration::Enabled)?;
     let sourcemap = printed.take_sourcemap();
     let verbatim_ranges = printed.take_verbatim_ranges();
 

diff --git a/crates/biome_formatter/src/printer/mod.rs b/crates/biome_formatter/src/printer/mod.rs
@@ -394,6 +394,10 @@ impl<'a> Printer<'a> {
     }
 
     fn push_marker(&mut self, marker: SourceMarker) {
+        if self.options.source_map_generation().is_disabled() {
+            return;
+        }
+
         if let Some(last) = self.state.source_markers.last() {
             if last != &marker {
                 self.state.source_markers.push(marker)

diff --git a/crates/biome_formatter/src/printer/printer_options/mod.rs b/crates/biome_formatter/src/printer/printer_options/mod.rs
@@ -15,6 +15,10 @@ pub struct PrinterOptions {
 
     /// Whether the printer should use tabs or spaces to indent code and if spaces, by how many.
     pub indent_style: IndentStyle,
+
+    /// Should the printer generate a source map that allows mapping positions in the source document
+    /// to positions in the formatted document.
+    pub source_map_generation: SourceMapGeneration,
 }
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
@@ -81,10 +85,20 @@ impl PrinterOptions {
         self
     }
 
+    pub fn with_source_map_generation(mut self, source_map: SourceMapGeneration) -> Self {
+        self.source_map_generation = source_map;
+
+        self
+    }
+
     pub(crate) fn indent_style(&self) -> IndentStyle {
         self.indent_style
     }
 
+    pub const fn source_map_generation(&self) -> SourceMapGeneration {
+        self.source_map_generation
+    }
+
     /// Width of an indent in characters.
     pub(super) const fn indent_width(&self) -> IndentWidth {
         self.indent_width
@@ -103,6 +117,32 @@ impl Default for PrinterOptions {
             print_width: PrintWidth::default(),
             indent_style: Default::default(),
             line_ending: LineEnding::Lf,
+            source_map_generation: SourceMapGeneration::default(),
         }
     }
 }
+
+/// Configures whether the printer generates a source map that allows mapping
+/// positions in the source document to positions in the formatted code.
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Default)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+pub enum SourceMapGeneration {
+    /// The printer generates no source map.
+    #[default]
+    Disabled,
+
+    /// The printer generates a source map that allows mapping positions in the source document
+    /// to positions in the formatted document. The ability to map positions is useful for range formatting
+    /// or when trying to identify where to move the cursor so that it matches its position in the source document.
+    Enabled,
+}
+
+impl SourceMapGeneration {
+    pub const fn is_enabled(self) -> bool {
+        matches!(self, Self::Enabled)
+    }
+
+    pub const fn is_disabled(self) -> bool {
+        matches!(self, Self::Disabled)
+    }
+}
diff --git a/crates/biome_js_formatter/src/syntax_rewriter.rs b/crates/biome_js_formatter/src/syntax_rewriter.rs
@@ -465,7 +465,7 @@ fn has_type_cast_comment_or_skipped(trivia: &JsSyntaxTrivia) -> bool {
 mod tests {
     use super::JsFormatSyntaxRewriter;
     use crate::{JsFormatOptions, TextRange, format_node};
-    use biome_formatter::{SourceMarker, TransformSourceMap};
+    use biome_formatter::{SourceMapGeneration, SourceMarker, TransformSourceMap};
     use biome_js_parser::{JsParserOptions, parse, parse_module};
     use biome_js_syntax::{
         JsArrayExpression, JsBinaryExpression, JsExpressionStatement, JsFileSource,
@@ -847,7 +847,9 @@ mod tests {
 
         let formatted =
             format_node(JsFormatOptions::new(JsFileSource::default()), &transformed).unwrap();
-        let printed = formatted.print().unwrap();
+        let printed = formatted
+            .print_with_indent(0, SourceMapGeneration::Enabled)
+            .unwrap();
 
         assert_eq!(printed.as_code(), "(a * b * c) / 3;\n");
 

diff --git a/crates/biome_js_semantic/src/format_semantic_model.rs b/crates/biome_js_semantic/src/format_semantic_model.rs
@@ -1,7 +1,7 @@
 use biome_formatter::prelude::*;
 use biome_formatter::{
     FormatContext, FormatOptions, IndentStyle, IndentWidth, LineEnding, LineWidth,
-    TransformSourceMap,
+    SourceMapGeneration, TransformSourceMap,
 };
 use biome_formatter::{format_args, write};
 use biome_js_syntax::TextSize;
@@ -33,6 +33,7 @@ impl FormatOptions for FormatSemanticModelOptions {
             print_width: self.line_width().into(),
             line_ending: self.line_ending(),
             indent_style: self.indent_style(),
+            source_map_generation: SourceMapGeneration::default(),
         }
     }
 }

diff --git a/crates/biome_js_type_info/src/format_type_info.rs b/crates/biome_js_type_info/src/format_type_info.rs
@@ -10,7 +10,7 @@ use crate::{
 use biome_formatter::prelude::*;
 use biome_formatter::{
     FormatContext, FormatOptions, IndentStyle, IndentWidth, LineEnding, LineWidth,
-    TransformSourceMap,
+    SourceMapGeneration, TransformSourceMap,
 };
 use biome_formatter::{format_args, write};
 use biome_js_syntax::TextSize;
@@ -44,6 +44,7 @@ impl FormatOptions for FormatTypeOptions {
             print_width: self.line_width().into(),
             line_ending: self.line_ending(),
             indent_style: self.indent_style(),
+            source_map_generation: SourceMapGeneration::default(),
         }
     }
 }

diff --git a/crates/biome_service/src/file_handlers/svelte.rs b/crates/biome_service/src/file_handlers/svelte.rs
@@ -7,7 +7,7 @@ use crate::file_handlers::{
 };
 use crate::settings::Settings;
 use crate::workspace::{DocumentFileSource, FixFileResult, PullActionsResult};
-use biome_formatter::Printed;
+use biome_formatter::{Printed, SourceMapGeneration};
 use biome_fs::BiomePath;
 use biome_html_syntax::HtmlLanguage;
 use biome_js_formatter::format_node;
@@ -157,7 +157,7 @@ fn format(
     };
     let tree = parse.syntax();
     let formatted = format_node(options, &tree)?;
-    match formatted.print_with_indent(indent_amount) {
+    match formatted.print_with_indent(indent_amount, SourceMapGeneration::Disabled) {
         Ok(printed) => Ok(printed),
         Err(error) => {
             error!("The file {} couldn't be formatted", biome_path.as_str());

diff --git a/crates/biome_service/src/file_handlers/vue.rs b/crates/biome_service/src/file_handlers/vue.rs
@@ -7,7 +7,7 @@ use crate::file_handlers::{
 };
 use crate::settings::Settings;
 use crate::workspace::{DocumentFileSource, FixFileResult, PullActionsResult};
-use biome_formatter::Printed;
+use biome_formatter::{Printed, SourceMapGeneration};
 use biome_fs::BiomePath;
 use biome_html_syntax::HtmlLanguage;
 use biome_js_formatter::format_node;
@@ -157,7 +157,7 @@ fn format(
     };
     let tree = parse.syntax();
     let formatted = format_node(options, &tree)?;
-    match formatted.print_with_indent(indent_amount) {
+    match formatted.print_with_indent(indent_amount, SourceMapGeneration::Disabled) {
         Ok(printed) => Ok(printed),
         Err(error) => {
             error!("The file {} couldn't be formatted", biome_path.as_str());