refactor(eslint/default-case-last): simplify default case last check in switch statement (#13529)

antoinezanardi · web-flow · commit 1425da281eb2 · 2025-09-06T19:28:00.000+07:00
Related to #13515 Thanks @overlookmotel for the suggestion, indeed clearer 💪🏻.
diff --git a/crates/oxc_linter/src/rules/eslint/default_case_last.rs b/crates/oxc_linter/src/rules/eslint/default_case_last.rs
@@ -91,14 +91,11 @@ impl Rule for DefaultCaseLast {
         let AstKind::SwitchStatement(switch) = node.kind() else {
             return;
         };
+
         let cases = &switch.cases;
-        if let Some((index, default_clause)) =
-            cases.iter().enumerate().find(|(_, c)| c.test.is_none())
-        {
-            let is_default_clause_last = index == cases.len() - 1;
-            if !is_default_clause_last {
-                ctx.diagnostic(default_case_last_diagnostic(default_clause.span));
-            }
+        let cases_without_last = &cases[..cases.len().saturating_sub(1)];
+        if let Some(default_clause) = cases_without_last.iter().find(|c| c.test.is_none()) {
+            ctx.diagnostic(default_case_last_diagnostic(default_clause.span));
         }
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -91,14 +91,11 @@ impl Rule for DefaultCaseLast {`
`91`	`91`	`let AstKind::SwitchStatement(switch) = node.kind() else {`
`92`	`92`	`return;`
`93`	`93`	`};`
	`94`	`+`
`94`	`95`	`let cases = &switch.cases;`
`95`		`- if let Some((index, default_clause)) =`
`96`		`- cases.iter().enumerate().find(\|(_, c)\| c.test.is_none())`
`97`		`- {`
`98`		`- let is_default_clause_last = index == cases.len() - 1;`
`99`		`- if !is_default_clause_last {`
`100`		`- ctx.diagnostic(default_case_last_diagnostic(default_clause.span));`
`101`		`- }`
	`96`	`+ let cases_without_last = &cases[..cases.len().saturating_sub(1)];`
	`97`	`+ if let Some(default_clause) = cases_without_last.iter().find(\|c\| c.test.is_none()) {`
	`98`	`+ ctx.diagnostic(default_case_last_diagnostic(default_clause.span));`
`102`	`99`	`}`
`103`	`100`	`}`
`104`	`101`	`}`