Handle ternary operator in arrays and objects.

src/twig.expression.js

@@ -260,6 +260,8 @@ module.exports = function (Twig) {
                     // Check if this is a ternary or object key being set
                     if (stack[stack.length - 1] && stack[stack.length - 1].value === '?') {
                         // Continue as normal for a ternary
+                        // Mark the ? operator as having a colon (full ternary, not shorthand)
+                        stack[stack.length - 1].hasColon = true;
                     } else {
                         // This is not a ternary so we push the token to the output where it can be handled
                         //   when the assocated object is closed.
@@ -304,7 +306,7 @@ module.exports = function (Twig) {
                             }
                         });
                 } else {
-                    Twig.expression.operator.parse(token.value, stack);
+                    Twig.expression.operator.parse(token.value, stack, token);
                 }
             }
         },
@@ -339,7 +341,7 @@ module.exports = function (Twig) {
                 stack.push(operator);
             },
             parse(token, stack) {
-                Twig.expression.operator.parse(token.value, stack);
+                Twig.expression.operator.parse(token.value, stack, token);
             }
         },
         {

src/twig.expression.operator.js

@@ -157,19 +157,34 @@ module.exports = function (Twig) {
      *
      * Returns the updated stack.
      */
-    Twig.expression.operator.parse = function (operator, stack) {
+    Twig.expression.operator.parse = function (operator, stack, token) {
         Twig.log.trace('Twig.expression.operator.parse: ', 'Handling ', operator);
         let a;
         let b;
         let c;
 
-        if (operator === '?') {
-            c = stack.pop();
-        }
+        // For shorthand ternary (a ? b), we only need 2 operands
+        // Check if this is a shorthand ternary by seeing if the token has a hasColon flag
+        const isShorthandTernary = (operator === '?' && token && !token.hasColon);
 
-        b = stack.pop();
-        if (operator !== 'not') {
-            a = stack.pop();
+        if (operator === '?') {
+            if (isShorthandTernary) {
+                // Shorthand ternary: only pop 2 operands
+                b = stack.pop();
+                a = stack.pop();
+                c = '';
+            } else {
+                // Full ternary: pop 3 operands
+                c = stack.pop();
+                b = stack.pop();
+                a = stack.pop();
+            }
+        } else {
+            // Other operators
+            b = stack.pop();
+            if (operator !== 'not') {
+                a = stack.pop();
+            }
         }
 
         if (operator !== 'in' && operator !== 'not in' && operator !== '??') {
@@ -219,13 +234,7 @@ module.exports = function (Twig) {
 
                 break;
             case '?':
-                if (a === undefined) {
-                    // An extended ternary.
-                    a = b;
-                    b = c;
-                    c = undefined;
-                }
-
+                // a, b, c are already set correctly based on isShorthandTernary
                 if (Twig.lib.boolval(a)) {
                     stack.push(b);
                 } else {

test/test.expressions.js

@@ -372,6 +372,19 @@ describe('Twig.js Expressions ->', function () {
             testTemplate.render({test: null}).should.equal('false');
             testTemplate.render({test: undefined}).should.equal('false');
         });
+        it('should support the ternary operator inside objects', function () {
+            const testTemplate = twig({data: '{% set classes = { "a-button": true, "modifier": modifier ? modifier, "false":false}|json_encode %}{{ classes }}'});
+            const output = testTemplate.render({});
+
+            output.should.equal('{"a-button":true,"modifier":"","false":false}');
+        });
+
+        it('should support the ternary operator inside arrays', function () {
+            const testTemplate = twig({data: '{% set classes = [ "a-button", modifier ? modifier, false]|json_encode %}{{ classes }}'});
+            const output = testTemplate.render({});
+
+            output.should.equal('["a-button","",false]');
+        });
 
         it('should support in/containment functionality for arrays', function () {
             let testTemplate;