fix(noNestedTernary): detect nested ternaries wrapped in parentheses (#8086)

Co-authored-by: Carson McManus <[email protected]>

Author: matanshavit

.changeset/fix-nested-ternary-parentheses.md

@@ -0,0 +1,19 @@
+---
+"@biomejs/biome": patch
+---
+
+Fixed [#8045](https://github.com/biomejs/biome/issues/8045): The [`noNestedTernary`](https://biomejs.dev/linter/rules/no-nested-ternary/) rule now correctly detects nested ternary expressions even when they are wrapped in parentheses (e.g. `foo ? (bar ? 1 : 2) : 3`).
+
+Previously, the rule would not flag nested ternaries like `foo ? (bar ? 1 : 2) : 3` because the parentheses prevented detection. The rule now looks through parentheses to identify nested conditionals.
+
+**Previously not detected (now flagged):**
+
+```js
+const result = foo ? (bar ? 1 : 2) : 3;
+```
+
+**Still valid (non-nested with parentheses):**
+
+```js
+const result = (foo ? bar : baz);
+```

crates/biome_js_analyze/src/lint/style/no_nested_ternary.rs

@@ -63,11 +63,11 @@ impl Rule for NoNestedTernary {
         let alternate = node.alternate().ok()?;
         let consequent = node.consequent().ok()?;
 
-        if let AnyJsExpression::JsConditionalExpression(expr) = consequent {
+        if let AnyJsExpression::JsConditionalExpression(expr) = consequent.omit_parentheses() {
             return Some(expr.range());
         }
 
-        if let AnyJsExpression::JsConditionalExpression(expr) = alternate {
+        if let AnyJsExpression::JsConditionalExpression(expr) = alternate.omit_parentheses() {
             return Some(expr.range());
         }
 

crates/biome_js_analyze/tests/specs/style/noNestedTernary/invalid.js

@@ -1,3 +1,19 @@
 var thing = foo ? bar : baz === qux ? quxx : foobar;
 
-foo ? baz === qux ? quxx() : foobar() : bar();
+foo ? baz === qux ? quxx() : foobar() : bar();
+
+var thing1 = foo ? (bar ? 1 : 2) : 3;
+
+var thing2 = foo ? 1 : (bar ? 2 : 3);
+
+var thing3 = foo ? ((bar ? 1 : 2)) : 3;
+
+var thing4 = foo ? 1 : ((bar ? 2 : 3));
+
+var thing5 = foo ? (baz === qux ? quxx : foobar) : bar;
+
+const case1 = val ? (Math.random() ? 1 : 2) : 3;
+
+const case2 = val ? 1 : Math.random() ? 2 : 3;
+
+const case3 = (val ? (Math.random() ? 1 : 2) : 3);

crates/biome_js_analyze/tests/specs/style/noNestedTernary/invalid.js.snap

@@ -7,6 +7,23 @@ expression: invalid.js
 var thing = foo ? bar : baz === qux ? quxx : foobar;
 
 foo ? baz === qux ? quxx() : foobar() : bar();
+
+var thing1 = foo ? (bar ? 1 : 2) : 3;
+
+var thing2 = foo ? 1 : (bar ? 2 : 3);
+
+var thing3 = foo ? ((bar ? 1 : 2)) : 3;
+
+var thing4 = foo ? 1 : ((bar ? 2 : 3));
+
+var thing5 = foo ? (baz === qux ? quxx : foobar) : bar;
+
+const case1 = val ? (Math.random() ? 1 : 2) : 3;
+
+const case2 = val ? 1 : Math.random() ? 2 : 3;
+
+const case3 = (val ? (Math.random() ? 1 : 2) : 3);
+
 ```
 
 # Diagnostics
@@ -36,6 +53,159 @@ invalid.js:3:7 lint/style/noNestedTernary ━━━━━━━━━━━━
     2 │ 
   > 3 │ foo ? baz === qux ? quxx() : foobar() : bar();
       │       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    4 │ 
+    5 │ var thing1 = foo ? (bar ? 1 : 2) : 3;
+  
+  i Nesting ternary expressions can make code more difficult to understand.
+  
+  i Convert nested ternary expression into if-else statements or separate the conditions to make the logic easier to understand.
+  
+
+```
+
+```
+invalid.js:5:21 lint/style/noNestedTernary ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i Do not nest ternary expressions.
+  
+    3 │ foo ? baz === qux ? quxx() : foobar() : bar();
+    4 │ 
+  > 5 │ var thing1 = foo ? (bar ? 1 : 2) : 3;
+      │                     ^^^^^^^^^^^
+    6 │ 
+    7 │ var thing2 = foo ? 1 : (bar ? 2 : 3);
+  
+  i Nesting ternary expressions can make code more difficult to understand.
+  
+  i Convert nested ternary expression into if-else statements or separate the conditions to make the logic easier to understand.
+  
+
+```
+
+```
+invalid.js:7:25 lint/style/noNestedTernary ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i Do not nest ternary expressions.
+  
+    5 │ var thing1 = foo ? (bar ? 1 : 2) : 3;
+    6 │ 
+  > 7 │ var thing2 = foo ? 1 : (bar ? 2 : 3);
+      │                         ^^^^^^^^^^^
+    8 │ 
+    9 │ var thing3 = foo ? ((bar ? 1 : 2)) : 3;
+  
+  i Nesting ternary expressions can make code more difficult to understand.
+  
+  i Convert nested ternary expression into if-else statements or separate the conditions to make the logic easier to understand.
+  
+
+```
+
+```
+invalid.js:9:22 lint/style/noNestedTernary ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i Do not nest ternary expressions.
+  
+     7 │ var thing2 = foo ? 1 : (bar ? 2 : 3);
+     8 │ 
+   > 9 │ var thing3 = foo ? ((bar ? 1 : 2)) : 3;
+       │                      ^^^^^^^^^^^
+    10 │ 
+    11 │ var thing4 = foo ? 1 : ((bar ? 2 : 3));
+  
+  i Nesting ternary expressions can make code more difficult to understand.
+  
+  i Convert nested ternary expression into if-else statements or separate the conditions to make the logic easier to understand.
+  
+
+```
+
+```
+invalid.js:11:26 lint/style/noNestedTernary ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i Do not nest ternary expressions.
+  
+     9 │ var thing3 = foo ? ((bar ? 1 : 2)) : 3;
+    10 │ 
+  > 11 │ var thing4 = foo ? 1 : ((bar ? 2 : 3));
+       │                          ^^^^^^^^^^^
+    12 │ 
+    13 │ var thing5 = foo ? (baz === qux ? quxx : foobar) : bar;
+  
+  i Nesting ternary expressions can make code more difficult to understand.
+  
+  i Convert nested ternary expression into if-else statements or separate the conditions to make the logic easier to understand.
+  
+
+```
+
+```
+invalid.js:13:21 lint/style/noNestedTernary ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i Do not nest ternary expressions.
+  
+    11 │ var thing4 = foo ? 1 : ((bar ? 2 : 3));
+    12 │ 
+  > 13 │ var thing5 = foo ? (baz === qux ? quxx : foobar) : bar;
+       │                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    14 │ 
+    15 │ const case1 = val ? (Math.random() ? 1 : 2) : 3;
+  
+  i Nesting ternary expressions can make code more difficult to understand.
+  
+  i Convert nested ternary expression into if-else statements or separate the conditions to make the logic easier to understand.
+  
+
+```
+
+```
+invalid.js:15:22 lint/style/noNestedTernary ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i Do not nest ternary expressions.
+  
+    13 │ var thing5 = foo ? (baz === qux ? quxx : foobar) : bar;
+    14 │ 
+  > 15 │ const case1 = val ? (Math.random() ? 1 : 2) : 3;
+       │                      ^^^^^^^^^^^^^^^^^^^^^
+    16 │ 
+    17 │ const case2 = val ? 1 : Math.random() ? 2 : 3;
+  
+  i Nesting ternary expressions can make code more difficult to understand.
+  
+  i Convert nested ternary expression into if-else statements or separate the conditions to make the logic easier to understand.
+  
+
+```
+
+```
+invalid.js:17:25 lint/style/noNestedTernary ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i Do not nest ternary expressions.
+  
+    15 │ const case1 = val ? (Math.random() ? 1 : 2) : 3;
+    16 │ 
+  > 17 │ const case2 = val ? 1 : Math.random() ? 2 : 3;
+       │                         ^^^^^^^^^^^^^^^^^^^^^
+    18 │ 
+    19 │ const case3 = (val ? (Math.random() ? 1 : 2) : 3);
+  
+  i Nesting ternary expressions can make code more difficult to understand.
+  
+  i Convert nested ternary expression into if-else statements or separate the conditions to make the logic easier to understand.
+  
+
+```
+
+```
+invalid.js:19:23 lint/style/noNestedTernary ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i Do not nest ternary expressions.
+  
+    17 │ const case2 = val ? 1 : Math.random() ? 2 : 3;
+    18 │ 
+  > 19 │ const case3 = (val ? (Math.random() ? 1 : 2) : 3);
+       │                       ^^^^^^^^^^^^^^^^^^^^^
+    20 │ 
   
   i Nesting ternary expressions can make code more difficult to understand.
   

crates/biome_js_analyze/tests/specs/style/noNestedTernary/valid.js

@@ -1,12 +1,18 @@
 /* should not generate diagnostics */
-const thing = foo ? bar : foobar;
+const thing1 = foo ? bar : foobar;
 
-let thing;
+let thing2;
 
 if (foo) {
-  thing = bar;
+  thing2 = bar;
 } else if (baz === qux) {
-  thing = quxx;
+  thing2 = quxx;
 } else {
-  thing = foobar;
-}
+  thing2 = foobar;
+}
+
+const thing3 = (foo ? bar : baz);
+
+const thing4 = foo ? (bar) : (baz);
+
+const thing5 = ((foo ? bar : baz));

crates/biome_js_analyze/tests/specs/style/noNestedTernary/valid.js.snap

@@ -1,20 +1,26 @@
 ---
 source: crates/biome_js_analyze/tests/spec_tests.rs
 expression: valid.js
-snapshot_kind: text
 ---
 # Input
 ```js
 /* should not generate diagnostics */
-const thing = foo ? bar : foobar;
+const thing1 = foo ? bar : foobar;
 
-let thing;
+let thing2;
 
 if (foo) {
-  thing = bar;
+  thing2 = bar;
 } else if (baz === qux) {
-  thing = quxx;
+  thing2 = quxx;
 } else {
-  thing = foobar;
+  thing2 = foobar;
 }
+
+const thing3 = (foo ? bar : baz);
+
+const thing4 = foo ? (bar) : (baz);
+
+const thing5 = ((foo ? bar : baz));
+
 ```