feat(formatter): add option json.formatter.trailingComma (#1948)

CHANGELOG.md

@@ -619,6 +619,10 @@ our [guidelines for writing a good changelog entry](https://github.com/biomejs/b
 
 ### Formatter
 
+#### New features
+
+- Add option `json.formatter.trailingComma`, to provide a better control over the trailing comma in JSON/JSONC files. Its default value is `"none"`.
+
 #### Bug fixes
 
 - Fix [#1178](https://github.com/biomejs/biome/issues/1178), where the line ending option wasn't correctly applied.

crates/biome_cli/src/commands/rage.rs

@@ -263,6 +263,7 @@ impl Display for RageConfiguration<'_, '_> {
                             {KeyValuePair("Indent size", markup!({DebugDisplayOption(json_formatter_configuration.indent_size)}))}
                             {KeyValuePair("Line ending", markup!({DebugDisplayOption(json_formatter_configuration.line_ending)}))}
                             {KeyValuePair("Line width", markup!({DebugDisplayOption(json_formatter_configuration.line_width.map(|lw| lw.get()))}))}
+                            {KeyValuePair("Trailing Commas", markup!({DebugDisplayOption(json_formatter_configuration.trailing_commas)}))}
                         ).fmt(fmt)?;
                     }
 

crates/biome_cli/src/execute/migrate.rs

@@ -63,7 +63,7 @@ pub(crate) fn run(migrate_payload: MigratePayload) -> Result<(), CliDiagnostic>
         path: biome_path.clone(),
         content: configuration_content.to_string(),
         version: 0,
-        document_file_source: JsonFileSource::json().into(),
+        document_file_source: Some(JsonFileSource::json().into()),
     })?;
 
     let parsed = parse_json_with_cache(

crates/biome_cli/src/execute/process_file/workspace_file.rs

@@ -2,7 +2,7 @@ use crate::execute::diagnostics::{ResultExt, ResultIoExt};
 use crate::execute::process_file::SharedTraversalOptions;
 use biome_diagnostics::{category, Error};
 use biome_fs::{BiomePath, File, OpenOptions};
-use biome_service::workspace::{DocumentFileSource, FileGuard, OpenFileParams};
+use biome_service::workspace::{FileGuard, OpenFileParams};
 use biome_service::{Workspace, WorkspaceError};
 use std::path::{Path, PathBuf};
 
@@ -36,7 +36,7 @@ impl<'ctx, 'app> WorkspaceFile<'ctx, 'app> {
         let guard = FileGuard::open(
             ctx.workspace,
             OpenFileParams {
-                document_file_source: DocumentFileSource::from_path(&biome_path),
+                document_file_source: None,
                 path: biome_path,
                 version: 0,
                 content: input.clone(),

crates/biome_cli/src/execute/std_in.rs

@@ -8,9 +8,8 @@ use biome_diagnostics::Diagnostic;
 use biome_diagnostics::PrintDiagnostic;
 use biome_fs::BiomePath;
 use biome_service::workspace::{
-    ChangeFileParams, DocumentFileSource, FeaturesBuilder, FixFileParams, FormatFileParams,
-    OpenFileParams, OrganizeImportsParams, PullDiagnosticsParams, RuleCategories,
-    SupportsFeatureParams,
+    ChangeFileParams, FeaturesBuilder, FixFileParams, FormatFileParams, OpenFileParams,
+    OrganizeImportsParams, PullDiagnosticsParams, RuleCategories, SupportsFeatureParams,
 };
 use biome_service::WorkspaceError;
 use std::borrow::Cow;
@@ -49,7 +48,7 @@ pub(crate) fn run<'a>(
                 path: biome_path.clone(),
                 version: 0,
                 content: content.into(),
-                document_file_source: DocumentFileSource::default(),
+                document_file_source: None,
             })?;
             let printed = workspace.format_file(FormatFileParams { path: biome_path })?;
 
@@ -72,7 +71,7 @@ pub(crate) fn run<'a>(
             path: biome_path.clone(),
             version: 0,
             content: content.into(),
-            document_file_source: DocumentFileSource::default(),
+            document_file_source: None,
         })?;
         // apply fix file of the linter
         let file_features = workspace.file_features(SupportsFeatureParams {

crates/biome_cli/tests/commands/format.rs

@@ -2265,7 +2265,7 @@ fn format_json_when_allow_trailing_commas_write() {
 
     assert!(result.is_ok(), "run_cli returned {result:?}");
 
-    assert_file_contents(&fs, Path::new(file_path), "{\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n}\n");
+    assert_file_contents(&fs, Path::new(file_path), "{\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\"\n}\n");
 
     assert_cli_snapshot(SnapshotPayload::new(
         module_path!(),
@@ -2276,6 +2276,94 @@ fn format_json_when_allow_trailing_commas_write() {
     ));
 }
 
+#[test]
+fn format_omits_json_trailing_comma() {
+    let mut fs = MemoryFileSystem::default();
+    let mut console = BufferConsole::default();
+
+    let config_json = r#"{
+    "json": {
+        "parser": { "allowTrailingCommas": true },
+        "formatter": { "trailingCommas": "none" }
+    }
+}"#;
+    let biome_config = "biome.json";
+    let code = r#"{   "loreum_ipsum_lorem_ipsum":   "bar", "loreum_ipsum_lorem_ipsum":   "bar", "loreum_ipsum_lorem_ipsum":   "bar", "loreum_ipsum_lorem_ipsum":   "bar", "loreum_ipsum_lorem_ipsum":   "bar",
+}"#;
+    let file_path = Path::new("file.json");
+    fs.insert(file_path.into(), code.as_bytes());
+    fs.insert(biome_config.into(), config_json);
+
+    let result = run_cli(
+        DynRef::Borrowed(&mut fs),
+        &mut console,
+        Args::from(
+            [
+                ("format"),
+                "--write",
+                file_path.as_os_str().to_str().unwrap(),
+            ]
+            .as_slice(),
+        ),
+    );
+
+    assert!(result.is_ok(), "run_cli returned {result:?}");
+
+    assert_file_contents(&fs, Path::new(file_path), "{\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\"\n}\n");
+
+    assert_cli_snapshot(SnapshotPayload::new(
+        module_path!(),
+        "format_omits_json_trailing_comma",
+        fs,
+        console,
+        result,
+    ));
+}
+
+#[test]
+fn format_omits_json_trailing_comma_omit() {
+    let mut fs = MemoryFileSystem::default();
+    let mut console = BufferConsole::default();
+
+    let config_json = r#"{
+    "json": {
+        "parser": { "allowTrailingCommas": true },
+        "formatter": { "trailingCommas": "all" }
+    }
+}"#;
+    let biome_config = "biome.json";
+    let code = r#"{   "loreum_ipsum_lorem_ipsum":   "bar", "loreum_ipsum_lorem_ipsum":   "bar", "loreum_ipsum_lorem_ipsum":   "bar", "loreum_ipsum_lorem_ipsum":   "bar", "loreum_ipsum_lorem_ipsum":   "bar",
+}"#;
+    let file_path = Path::new("file.json");
+    fs.insert(file_path.into(), code.as_bytes());
+    fs.insert(biome_config.into(), config_json);
+
+    let result = run_cli(
+        DynRef::Borrowed(&mut fs),
+        &mut console,
+        Args::from(
+            [
+                ("format"),
+                "--write",
+                file_path.as_os_str().to_str().unwrap(),
+            ]
+            .as_slice(),
+        ),
+    );
+
+    assert!(result.is_ok(), "run_cli returned {result:?}");
+
+    assert_file_contents(&fs, Path::new(file_path), "{\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n\t\"loreum_ipsum_lorem_ipsum\": \"bar\",\n}\n");
+
+    assert_cli_snapshot(SnapshotPayload::new(
+        module_path!(),
+        "format_omits_json_trailing_comma_omit",
+        fs,
+        console,
+        result,
+    ));
+}
+
 #[test]
 fn treat_known_json_files_as_jsonc_files() {
     let mut fs = MemoryFileSystem::default();

crates/biome_cli/tests/snapshots/main_commands_check/check_help.snap

@@ -70,6 +70,8 @@ The configuration that is contained inside the file `biome.json`
                               languages) files.
         --json-formatter-line-width=NUMBER  What's the max width of a line applied to JSON (and its super
                               languages) files. Defaults to 80.
+        --json-formatter-trailing-commas=<omit|allow>  Print trailing commas wherever possible in multi-line
+                              comma-separated syntactic structures. Defaults to "omit".
 
 Global options applied to all commands
         --colors=<off|force>  Set the formatting mode for markup: "off" prints everything as plain text,

crates/biome_cli/tests/snapshots/main_commands_ci/ci_help.snap

@@ -72,6 +72,8 @@ The configuration that is contained inside the file `biome.json`
                               languages) files.
         --json-formatter-line-width=NUMBER  What's the max width of a line applied to JSON (and its super
                               languages) files. Defaults to 80.
+        --json-formatter-trailing-commas=<omit|allow>  Print trailing commas wherever possible in multi-line
+                              comma-separated syntactic structures. Defaults to "omit".
 
 Global options applied to all commands
         --colors=<off|force>  Set the formatting mode for markup: "off" prints everything as plain text,

crates/biome_cli/tests/snapshots/main_commands_format/format_help.snap

@@ -106,6 +106,8 @@ Available options:
                               languages) files.
         --json-formatter-line-width=NUMBER  What's the max width of a line applied to JSON (and its super
                               languages) files. Defaults to 80.
+        --json-formatter-trailing-commas=<omit|allow>  Print trailing commas wherever possible in multi-line
+                              comma-separated syntactic structures. Defaults to "omit".
         --stdin-file-path=PATH  Use this option when you want to format code piped from `stdin`, and
                               print the output to `stdout`.
                               The file doesn't need to exist on disk, what matters is the extension of

crates/biome_cli/tests/snapshots/main_commands_format/format_json_when_allow_trailing_commas.snap

@@ -45,7 +45,7 @@ file.json format ━━━━━━━━━━━━━━━━━━━━━
     3   │ - ········1,
     4   │ - ····],
     5   │ - }
-      2 │ + → "array":·[1],
+      2 │ + → "array":·[1]
       3 │ + }
       4 │ + 
   

crates/biome_cli/tests/snapshots/main_commands_format/format_json_when_allow_trailing_commas_write.snap

@@ -20,7 +20,7 @@ expression: content
 	"loreum_ipsum_lorem_ipsum": "bar",
 	"loreum_ipsum_lorem_ipsum": "bar",
 	"loreum_ipsum_lorem_ipsum": "bar",
-	"loreum_ipsum_lorem_ipsum": "bar",
+	"loreum_ipsum_lorem_ipsum": "bar"
 }
 
 ```

crates/biome_cli/tests/snapshots/main_commands_format/format_omits_json_trailing_comma.snap

@@ -0,0 +1,35 @@
+---
+source: crates/biome_cli/tests/snap_test.rs
+expression: content
+---
+## `biome.json`
+
+```json
+{
+  "json": {
+    "parser": { "allowTrailingCommas": true },
+    "formatter": { "trailingCommas": "none" }
+  }
+}
+```
+
+## `file.json`
+
+```json
+{
+	"loreum_ipsum_lorem_ipsum": "bar",
+	"loreum_ipsum_lorem_ipsum": "bar",
+	"loreum_ipsum_lorem_ipsum": "bar",
+	"loreum_ipsum_lorem_ipsum": "bar",
+	"loreum_ipsum_lorem_ipsum": "bar"
+}
+
+```
+
+# Emitted Messages
+
+```block
+Formatted 1 file in <TIME>. Fixed 1 file.
+```
+
+

crates/biome_cli/tests/snapshots/main_commands_format/format_omits_json_trailing_comma_omit.snap

@@ -0,0 +1,35 @@
+---
+source: crates/biome_cli/tests/snap_test.rs
+expression: content
+---
+## `biome.json`
+
+```json
+{
+  "json": {
+    "parser": { "allowTrailingCommas": true },
+    "formatter": { "trailingCommas": "all" }
+  }
+}
+```
+
+## `file.json`
+
+```json
+{
+	"loreum_ipsum_lorem_ipsum": "bar",
+	"loreum_ipsum_lorem_ipsum": "bar",
+	"loreum_ipsum_lorem_ipsum": "bar",
+	"loreum_ipsum_lorem_ipsum": "bar",
+	"loreum_ipsum_lorem_ipsum": "bar",
+}
+
+```
+
+# Emitted Messages
+
+```block
+Formatted 1 file in <TIME>. Fixed 1 file.
+```
+
+

crates/biome_cli/tests/snapshots/main_commands_rage/with_formatter_configuration.snap

@@ -110,6 +110,7 @@ JSON Formatter:
   Indent size:                  unset
   Line ending:                  Lf
   Line width:                   100
+  Trailing Commas:              unset
 
 Server:
   Version:                      0.0.0

crates/biome_json_formatter/Cargo.toml

@@ -13,11 +13,16 @@ version              = "0.4.0"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-biome_diagnostics = { workspace = true }
-biome_formatter   = { workspace = true }
-biome_json_syntax = { workspace = true }
-biome_rowan       = { workspace = true }
-biome_suppression = { workspace = true }
+biome_deserialize        = { workspace = true }
+biome_deserialize_macros = { workspace = true }
+biome_diagnostics        = { workspace = true }
+biome_formatter          = { workspace = true }
+biome_json_syntax        = { workspace = true }
+biome_rowan              = { workspace = true }
+biome_suppression        = { workspace = true }
+schemars                 = { workspace = true, optional = true }
+serde                    = { workspace = true, features = ["derive"], optional = true }
+
 
 [dev-dependencies]
 biome_formatter_test = { path = "../biome_formatter_test" }
@@ -27,13 +32,15 @@ biome_json_parser    = { path = "../biome_json_parser" }
 biome_parser         = { path = "../biome_parser" }
 countme              = { workspace = true, features = ["enable"] }
 insta                = { workspace = true, features = ["glob"] }
-serde                = { version = "1", features = ["derive"] }
 serde_json           = { workspace = true }
 tests_macros         = { path = "../tests_macros" }
 
 # cargo-workspaces metadata
 [package.metadata.workspaces]
 independent = true
 
+[features]
+serde = ["dep:serde", "schemars"]
+
 [lints]
 workspace = true