Fix for else-if statements

crates/rome_js_analyze/src/analyzers/nursery/no_excessive_complexity.rs

@@ -11,9 +11,9 @@ use rome_deserialize::{
 };
 use rome_js_syntax::{
     AnyJsFunctionBody, JsBreakStatement, JsCatchClause, JsConditionalExpression,
-    JsContinueStatement, JsDoWhileStatement, JsFinallyClause, JsForInStatement, JsForOfStatement,
-    JsForStatement, JsIfStatement, JsLanguage, JsLogicalExpression, JsLogicalOperator,
-    JsSwitchStatement, JsWhileStatement, JsWithStatement,
+    JsContinueStatement, JsDoWhileStatement, JsElseClause, JsFinallyClause, JsForInStatement,
+    JsForOfStatement, JsForStatement, JsIfStatement, JsLanguage, JsLogicalExpression,
+    JsLogicalOperator, JsSwitchStatement, JsWhileStatement, JsWithStatement,
 };
 use rome_json_syntax::{JsonLanguage, JsonSyntaxNode};
 use rome_rowan::{AstNode, Language, SyntaxNode, SyntaxResult, TextRange, WalkEvent};
@@ -184,6 +184,15 @@ impl Visitor for CognitiveComplexityVisitor {
                             state.score += 1;
                             state.last_seen_operator = Some(operator);
                         }
+                    } else if let Some(alternate) =
+                        JsElseClause::cast_ref(node).and_then(|js_else| js_else.alternate().ok())
+                    {
+                        if alternate.as_js_if_statement().is_some() {
+                            // Prevent double nesting inside else-if.
+                            state.nesting_level = state.nesting_level.saturating_sub(1);
+                        } else {
+                            state.score += 1;
+                        }
                     } else {
                         // Reset the operator for every other type of node.
                         state.last_seen_operator = None;
@@ -204,6 +213,15 @@ impl Visitor for CognitiveComplexityVisitor {
                 } else if let Some(state) = self.stack.last_mut() {
                     if increases_nesting(node) {
                         state.nesting_level = state.nesting_level.saturating_sub(1);
+                    } else if let Some(alternate) =
+                        JsElseClause::cast_ref(node).and_then(|js_else| js_else.alternate().ok())
+                    {
+                        if alternate.as_js_if_statement().is_some() {
+                            // Prevent double nesting inside else-if.
+                            state.nesting_level += 1;
+                        } else {
+                            state.nesting_level = state.nesting_level.saturating_sub(1);
+                        }
                     }
                 }
             }

crates/rome_js_analyze/tests/specs/nursery/noExcessiveComplexity/simpleBranches2.js

@@ -0,0 +1,7 @@
+function simpleBranches2() {
+    if (firstCondition) {                 // +1
+        return 1;
+    } else if (secondCondition) {         // +1
+        return 2;
+    }
+}

crates/rome_js_analyze/tests/specs/nursery/noExcessiveComplexity/simpleBranches2.js.snap

@@ -0,0 +1,33 @@
+---
+source: crates/rome_js_analyze/tests/spec_tests.rs
+expression: simpleBranches2.js
+---
+# Input
+```js
+function simpleBranches2() {
+    if (firstCondition) {                 // +1
+        return 1;
+    } else if (secondCondition) {         // +1
+        return 2;
+    }
+}
+
+```
+
+# Diagnostics
+```
+simpleBranches2.js:1:10 lint/nursery/noExcessiveComplexity ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  ! Excessive complexity detected.
+  
+  > 1 │ function simpleBranches2() {
+      │          ^^^^^^^^^^^^^^^
+    2 │     if (firstCondition) {                 // +1
+    3 │         return 1;
+  
+  i Please refactor this function to reduce its complexity score from 2 to 1.
+  
+
+```
+
+

crates/rome_js_analyze/tests/specs/nursery/noExcessiveComplexity/simpleBranches2.options.json

@@ -0,0 +1,15 @@
+{
+	"$schema": "../../../../../../npm/rome/configuration_schema.json",
+	"linter": {
+		"rules": {
+			"nursery": {
+				"noExcessiveComplexity": {
+					"level": "error",
+					"options": {
+						"maxAllowedComplexity": 1
+					}
+				}
+			}
+		}
+	}
+}