fix(12077) line breaking with unary operators in conditional

changelog_unreleased/javascript/12087.md

@@ -0,0 +1,34 @@
+#### Constant line breaks for Conditional operators (#12087 by @islandryu)
+
+```js
+//--print-width=25
+// Input
+const a = foo == null ? bar : baz;
+
+const b = !fooooooooo ? bar : baz;
+
+const x = {
+  prop1: foo == null ? bar : baz,
+  prop1: !fooooooooo ? bar : baz,
+};
+
+// Prettier stable
+const a = foo == null ? bar : baz;
+
+const b = !fooooooooo ? bar : baz;
+
+const x = {
+  prop1: foo == null ? bar : baz,
+  prop1: !fooooooooo ? bar : baz,
+};
+
+// Prettier main
+const a = foo == null ? bar : baz;
+
+const b = !fooooooooo ? bar : baz;
+
+const x = {
+  prop1: foo == null ? bar : baz,
+  prop1: !fooooooooo ? bar : baz,
+};
+```

src/language-js/print/assignment.js

@@ -185,7 +185,10 @@ function shouldBreakAfterOperator(path, options, print, hasShortKey) {
       return true;
     case "ConditionalExpression": {
       const { test } = rightNode;
-      return isBinaryish(test) && !shouldInlineLogicalExpression(test);
+      return (
+        (test.type === "UnaryExpression" || isBinaryish(test)) &&
+        !shouldInlineLogicalExpression(test)
+      );
     }
     case "ClassExpression":
       return isNonEmptyArray(rightNode.decorators);