Add parenthesis when class expressions are left of a ternary (#428)

Fixes #426

src/fast-path.js

@@ -452,6 +452,10 @@ FPp.needsParens = function(assumeExpressionContext) {
           }
         case "MemberExpression":
           return name === "object" && parent.object === node;
+        case "ConditionalExpression":
+          if (parent.test === node) {
+            return true;
+          }
       }
 
       return false;

tests/classes/__snapshots__/jsfmt.spec.js.snap

@@ -305,3 +305,10 @@ declare var o: { p: number };
 (o: Class<C>); // error, object type incompatible with class type
 "
 `;
+
+exports[`test ternary.js 1`] = `
+"if (1) (class {}) ? 1 : 2;
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+if (1) (class {}) ? 1 : 2;
+"
+`;

tests/classes/ternary.js

@@ -0,0 +1 @@
+if (1) (class {}) ? 1 : 2;