feat(linter): eslint-plugin-unicorn switch-case-braces (#1054)

Rule taken from #684.

Tests taken from:
https://github.com/sindresorhus/eslint-plugin-unicorn/blob/main/test/switch-case-braces.mjs

crates/oxc_linter/src/rules.rs

@@ -148,6 +148,7 @@ mod unicorn {
     pub mod no_unnecessary_await;
     pub mod prefer_array_flat_map;
     pub mod prefer_logical_operator_over_ternary;
+    pub mod switch_case_braces;
     pub mod text_encoding_identifier_case;
     pub mod throw_new_error;
 }
@@ -262,6 +263,7 @@ oxc_macros::declare_all_lint_rules! {
     unicorn::no_unnecessary_await,
     unicorn::prefer_array_flat_map,
     unicorn::prefer_logical_operator_over_ternary,
+    unicorn::switch_case_braces,
     unicorn::text_encoding_identifier_case,
     unicorn::throw_new_error,
     react::jsx_key,

crates/oxc_linter/src/rules/unicorn/switch_case_braces.rs

@@ -0,0 +1,156 @@
+use oxc_ast::{ast::Statement, AstKind};
+use oxc_diagnostics::{
+    miette::{self, Diagnostic},
+    thiserror::Error,
+};
+use oxc_formatter::Gen;
+use oxc_macros::declare_oxc_lint;
+use oxc_span::{GetSpan, Span};
+
+use crate::{context::LintContext, fixer::Fix, rule::Rule, AstNode};
+
+#[derive(Debug, Error, Diagnostic)]
+#[error("eslint-plugin-unicorn(switch-case-braces):  Empty switch case shouldn't have braces and not-empty case should have braces around it.")]
+#[diagnostic(
+    severity(warning),
+    help("There is less visual clutter for empty cases and proper scope for non-empty cases.")
+)]
+struct SwitchCaseBracesDiagnostic(#[label] pub Span);
+
+#[derive(Debug, Default, Clone)]
+pub struct SwitchCaseBraces;
+
+declare_oxc_lint!(
+    /// ### What it does
+    /// Require empty switch cases to not have braces. Non-empty braces are required to have braces around them.
+    ///
+    /// ### Why is this bad?
+    /// There is less visual clutter for empty cases and proper scope for non-empty cases.
+    ///
+    /// ### Example
+    /// ```javascript
+    /// switch (num) {
+    ///     case 1: {
+    ///
+    ///     }
+    ///     case 2:
+    ///         console.log('Case 2');
+    ///         break;
+    /// }
+    /// ```
+    SwitchCaseBraces,
+    correctness
+);
+
+impl Rule for SwitchCaseBraces {
+    fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
+        let AstKind::SwitchStatement(switch) = node.kind() else { return };
+
+        if switch.cases.is_empty() {
+            return;
+        }
+
+        for case in &switch.cases {
+            for case_consequent in &case.consequent {
+                match case_consequent {
+                    Statement::BlockStatement(case_block) => {
+                        if case_block.body.is_empty() {
+                            ctx.diagnostic_with_fix(
+                                SwitchCaseBracesDiagnostic(case_block.span),
+                                || Fix::new("", case_block.span),
+                            );
+                        }
+                    }
+                    Statement::EmptyStatement(_) => {}
+                    _ => {
+                        let Some(first_statement) = &case.consequent.first() else {
+                            return;
+                        };
+                        let Some(last_statement) = &case.consequent.last() else {
+                            return;
+                        };
+
+                        let case_body_span = Span {
+                            start: first_statement.span().start,
+                            end: last_statement.span().end,
+                        };
+
+                        ctx.diagnostic_with_fix(SwitchCaseBracesDiagnostic(case_body_span), || {
+                            let modified_code = {
+                                let mut formatter = ctx.formatter();
+
+                                if let Some(case_test) = &case.test {
+                                    formatter.print_str(b"case ");
+                                    case_test.gen(&mut formatter);
+                                } else {
+                                    formatter.print_str(b"default");
+                                }
+
+                                formatter.print_colon();
+                                formatter.print_space();
+                                formatter.print(b'{');
+                                case.consequent.iter().for_each(|x| x.gen(&mut formatter));
+                                formatter.print(b'}');
+
+                                formatter.into_code()
+                            };
+
+                            Fix::new(modified_code, case.span)
+                        });
+
+                        // After first incorrect consequent we have to break to not repeat the work
+                        break;
+                    }
+                }
+            }
+        }
+    }
+}
+
+#[test]
+fn test() {
+    use crate::tester::Tester;
+
+    let pass = vec![
+        "switch(something) { case 1: case 2: {console.log('something'); break;}}",
+        "switch(foo){ case 1: { break; } }",
+        "switch(foo){ case 1: { ; /* <-- not empty */} }",
+        "switch(foo){ case 1: { {} /* <-- not empty */} }",
+        "switch(foo){ case 1: { break; } }",
+        "switch(foo){ default: { doSomething(); } }",
+    ];
+
+    let fail = vec![
+        "switch(something) { case 1: {} case 2: {console.log('something'); break;}}",
+        "switch(something) { case 1: case 2: console.log('something'); break;}",
+        "switch(foo) { case 1: {} case 2: {} default: { doSomething(); } }",
+        "switch(foo) { case 1: { /* fallthrough */ } default: {}/* fallthrough */ case 3: { doSomething(); break; } }",
+        "switch(foo) { default: doSomething(); }",
+        "switch(foo) { case 1: { doSomething(); } break; /* <-- This should be between braces */ }",
+        "switch(foo) { default: label: {} }",
+        "switch(something) { case 1: case 2: { console.log('something'); break; } case 3: console.log('something else'); }",
+
+    ];
+
+    let fix = vec![
+        (
+            "switch(something) { case 1: {} case 2: {console.log('something'); break;}}",
+            "switch(something) { case 1:  case 2: {console.log('something'); break;}}",
+            None,
+        ),
+        (
+            "switch(something) { case 1: {} case 2: console.log('something'); break;}",
+            "switch(something) { case 1:  case 2: {console.log(\"something\");\nbreak;\n}}",
+            None,
+        ),
+        (
+            "switch(foo) { default: doSomething(); }",
+            "switch(foo) { default: {doSomething();\n} }",
+            None,
+        ),
+    ];
+
+    Tester::new_without_config(SwitchCaseBraces::NAME, pass, fail)
+        .expect_fix(fix)
+        .test_and_snapshot();
+}

crates/oxc_linter/src/snapshots/switch_case_braces.snap

@@ -0,0 +1,75 @@
+---
+source: crates/oxc_linter/src/tester.rs
+expression: switch_case_braces
+---
+  ⚠ eslint-plugin-unicorn(switch-case-braces):  Empty switch case shouldn't have braces and not-empty case should have braces around it.
+   ╭─[switch_case_braces.tsx:1:1]
+ 1 │ switch(something) { case 1: {} case 2: {console.log('something'); break;}}
+   ·                             ──
+   ╰────
+  help: There is less visual clutter for empty cases and proper scope for non-empty cases.
+
+  ⚠ eslint-plugin-unicorn(switch-case-braces):  Empty switch case shouldn't have braces and not-empty case should have braces around it.
+   ╭─[switch_case_braces.tsx:1:1]
+ 1 │ switch(something) { case 1: case 2: console.log('something'); break;}
+   ·                                     ────────────────────────────────
+   ╰────
+  help: There is less visual clutter for empty cases and proper scope for non-empty cases.
+
+  ⚠ eslint-plugin-unicorn(switch-case-braces):  Empty switch case shouldn't have braces and not-empty case should have braces around it.
+   ╭─[switch_case_braces.tsx:1:1]
+ 1 │ switch(foo) { case 1: {} case 2: {} default: { doSomething(); } }
+   ·                       ──
+   ╰────
+  help: There is less visual clutter for empty cases and proper scope for non-empty cases.
+
+  ⚠ eslint-plugin-unicorn(switch-case-braces):  Empty switch case shouldn't have braces and not-empty case should have braces around it.
+   ╭─[switch_case_braces.tsx:1:1]
+ 1 │ switch(foo) { case 1: {} case 2: {} default: { doSomething(); } }
+   ·                                  ──
+   ╰────
+  help: There is less visual clutter for empty cases and proper scope for non-empty cases.
+
+  ⚠ eslint-plugin-unicorn(switch-case-braces):  Empty switch case shouldn't have braces and not-empty case should have braces around it.
+   ╭─[switch_case_braces.tsx:1:1]
+ 1 │ switch(foo) { case 1: { /* fallthrough */ } default: {}/* fallthrough */ case 3: { doSomething(); break; } }
+   ·                       ─────────────────────
+   ╰────
+  help: There is less visual clutter for empty cases and proper scope for non-empty cases.
+
+  ⚠ eslint-plugin-unicorn(switch-case-braces):  Empty switch case shouldn't have braces and not-empty case should have braces around it.
+   ╭─[switch_case_braces.tsx:1:1]
+ 1 │ switch(foo) { case 1: { /* fallthrough */ } default: {}/* fallthrough */ case 3: { doSomething(); break; } }
+   ·                                                      ──
+   ╰────
+  help: There is less visual clutter for empty cases and proper scope for non-empty cases.
+
+  ⚠ eslint-plugin-unicorn(switch-case-braces):  Empty switch case shouldn't have braces and not-empty case should have braces around it.
+   ╭─[switch_case_braces.tsx:1:1]
+ 1 │ switch(foo) { default: doSomething(); }
+   ·                        ──────────────
+   ╰────
+  help: There is less visual clutter for empty cases and proper scope for non-empty cases.
+
+  ⚠ eslint-plugin-unicorn(switch-case-braces):  Empty switch case shouldn't have braces and not-empty case should have braces around it.
+   ╭─[switch_case_braces.tsx:1:1]
+ 1 │ switch(foo) { case 1: { doSomething(); } break; /* <-- This should be between braces */ }
+   ·                       ─────────────────────────
+   ╰────
+  help: There is less visual clutter for empty cases and proper scope for non-empty cases.
+
+  ⚠ eslint-plugin-unicorn(switch-case-braces):  Empty switch case shouldn't have braces and not-empty case should have braces around it.
+   ╭─[switch_case_braces.tsx:1:1]
+ 1 │ switch(foo) { default: label: {} }
+   ·                        ─────────
+   ╰────
+  help: There is less visual clutter for empty cases and proper scope for non-empty cases.
+
+  ⚠ eslint-plugin-unicorn(switch-case-braces):  Empty switch case shouldn't have braces and not-empty case should have braces around it.
+   ╭─[switch_case_braces.tsx:1:1]
+ 1 │ switch(something) { case 1: case 2: { console.log('something'); break; } case 3: console.log('something else'); }
+   ·                                                                                  ──────────────────────────────
+   ╰────
+  help: There is less visual clutter for empty cases and proper scope for non-empty cases.
+
+