Expose functionality related to source map using the feature gate

Closes #2

Author: hyf0

.vscode/settings.json

@@ -1,5 +1,8 @@
 {
     "cSpell.words": [
         "outro"
+    ],
+    "rust-analyzer.cargo.features": [
+        "source_map"
     ]
 }

Cargo.toml

@@ -8,12 +8,14 @@ description = "manipulate string like wizards"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-glob = "0.3.1"
 index_vec = { version = "0.1.3" }
 rustc-hash = { version = "1.1.0" }
-vlq = "0.5.1"
-serde = {version = "1.0", features = ["derive"]}
-serde_json = "1.0"
+serde = { version = "1.0", features = ["derive"], optional = true }
+serde_json = { version = "1.0", optional = true }
+
+[features]
+# Enable source map functionality
+source_map = ["serde", "serde_json"]
 
 [dev-dependencies]
 glob = "0.3.1"

examples/source_map.rs

@@ -5,7 +5,7 @@ fn main() {
     let mut s = MagicString::new(demo);
 
     let update_options = UpdateOptions {
-        store_name: true,
+        keep_original: true,
         ..Default::default()
     };
     s.prepend("import React from 'react';\n")

src/lib.rs

@@ -1,12 +1,11 @@
+mod basic_types;
 mod chunk;
-mod decoded_map;
 mod joiner;
 mod locator;
 mod magic_string;
-mod mappings;
+#[cfg(feature = "source_map")]
 mod source_map;
 mod span;
-mod basic_types;
 
 type CowStr<'text> = BasicCowStr<'text>;
 
@@ -16,7 +15,8 @@ use basic_types::BasicCowStr;
 
 pub use crate::{
     joiner::{Joiner, JoinerOptions},
-    magic_string::{
-        mutation::UpdateOptions, source_map::SourceMapOptions, MagicString, MagicStringOptions,
-    },
+    magic_string::{mutation::UpdateOptions, MagicString, MagicStringOptions},
 };
+
+#[cfg(feature = "source_map")]
+pub use crate::magic_string::source_map::SourceMapOptions;

src/magic_string/mod.rs

@@ -1,4 +1,5 @@
 pub mod mutation;
+#[cfg(feature = "source_map")]
 pub mod source_map;
 
 use std::collections::VecDeque;
@@ -22,7 +23,6 @@ pub struct MagicString<'s> {
     intro: VecDeque<CowStr<'s>>,
     outro: VecDeque<CowStr<'s>>,
 
-    stored_names: Vec<Span>,
     source: CowStr<'s>,
     chunks: ChunkVec<'s>,
     first_chunk_idx: ChunkIdx,
@@ -54,7 +54,6 @@ impl<'s> MagicString<'s> {
             chunk_by_end: Default::default(),
             // setup options
             filename: options.filename,
-            stored_names: Default::default(),
         };
 
         magic_string.chunk_by_start.insert(0, initial_chunk_idx);

src/magic_string/mutation.rs

@@ -2,7 +2,8 @@ use crate::{chunk::EditOptions, CowStr, MagicString};
 
 #[derive(Debug, Default, Clone)]
 pub struct UpdateOptions {
-    pub store_name: bool,
+    /// `true` will store the original content in the `name` field of the generated sourcemap.
+    pub keep_original: bool,
 
     /// `true` will clear the `intro` and `outro` for the corresponding range.
     pub overwrite: bool,
@@ -36,7 +37,7 @@ impl<'text> MagicString<'text> {
             end,
             "".into(),
             UpdateOptions {
-                store_name: false,
+                keep_original: false,
                 overwrite: true,
             },
             false,
@@ -74,7 +75,7 @@ impl<'text> MagicString<'text> {
             content.into(),
             EditOptions {
                 overwrite: opts.overwrite,
-                store_name: opts.store_name,
+                store_name: opts.keep_original,
             },
         );
 

src/magic_string/source_map.rs

@@ -1,5 +1,6 @@
 use crate::{
-    decoded_map::DecodedMap, locator::Locator, mappings::Mappings, source_map::SourceMap,
+    locator::Locator,
+    source_map::{decoded_map::DecodedMap, mappings::Mappings, SourceMap},
     MagicString,
 };
 

src/decoded_map.rs renamed to src/source_map/decoded_map.rs

@@ -1,4 +1,6 @@
-use crate::{mappings::Mappings, source_map::SourceMap};
+use crate::source_map::SourceMap;
+
+use super::mappings::Mappings;
 
 #[derive(Debug)]
 pub struct DecodedMap {

src/mappings.rs renamed to src/source_map/mappings.rs

@@ -1,4 +1,9 @@
+// Notice that source map is designed based on utf-16 index, while rust [String] is based on utf-8 index.
+
+pub mod decoded_map;
+pub mod mappings;
 use serde::Serialize;
+
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct SourceMap {