feat(es): Support trailing commas in .swcrc (#6289)

crates/swc/Cargo.toml

@@ -49,7 +49,7 @@ base64 = "0.13.0"
 dashmap = "5.1.0"
 either = "1"
 indexmap = { version = "1.6.1", features = ["serde"] }
-json_comments = "0.2.0"
+jsonc-parser = { version = "0.21.0", features = ["serde"] }
 lru = "0.7.1"
 once_cell = "1.10.0"
 parking_lot = "0.12.0"

crates/swc/src/config/jsonc.json

@@ -0,0 +1,5 @@
+{
+    "jsc": {
+      // comment & trailing comma
+    },
+}

crates/swc/src/config/tests.rs

@@ -28,3 +28,9 @@ fn issue_1532() {
     let err = res.expect_err("should fail");
     assert!(err.to_string().contains("unknown variant `esnext`"));
 }
+
+#[test]
+fn jsonc() {
+    let rc = parse_swcrc(include_str!("jsonc.json")).expect("failed to parse");
+    dbg!(&rc);
+}

crates/swc/src/lib.rs

@@ -122,7 +122,7 @@ use anyhow::{bail, Context, Error};
 use atoms::JsWord;
 use common::{collections::AHashMap, comments::SingleThreadedComments, errors::HANDLER};
 use config::{IsModule, JsMinifyCommentOption, JsMinifyOptions, OutputCharset};
-use json_comments::StripComments;
+use jsonc_parser::{parse_to_serde_value, ParseOptions};
 use once_cell::sync::Lazy;
 use serde::Serialize;
 use serde_json::error::Category;
@@ -1175,13 +1175,21 @@ fn parse_swcrc(s: &str) -> Result<Rc, Error> {
         ))
     }
 
-    if let Ok(v) = serde_json::from_reader(StripComments::new(
-        s.trim_start_matches('\u{feff}').as_bytes(),
-    )) {
-        return Ok(v);
+    let v = parse_to_serde_value(
+        s.trim_start_matches('\u{feff}'),
+        &ParseOptions {
+            allow_comments: true,
+            allow_trailing_commas: true,
+            allow_loose_object_property_names: false,
+        },
+    )?
+    .ok_or_else(|| Error::msg("failed to deserialize empty .swcrc (json) file"))?;
+
+    if let Ok(rc) = serde_json::from_value(v.clone()) {
+        return Ok(rc);
     }
 
-    serde_json::from_reader::<StripComments<&[u8]>, Config>(StripComments::new(s.as_bytes()))
+    serde_json::from_value(v)
         .map(Rc::Single)
         .map_err(convert_json_err)
 }