Cast arrays to boolean values unless checking their contents

src/twig.expression.operator.js

@@ -123,6 +123,16 @@ module.exports = function (Twig) {
         b = stack.pop();
         a = stack.pop();
 
+        if (operator !== 'in' && operator !== 'not in') {
+            if (a && Array.isArray(a)) {
+                a = a.length;
+            }
+
+            if (b && Array.isArray(b)) {
+                b = b.length;
+            }
+        }
+
         switch (operator) {
             case ':':
                 // Ignore

test/test.expressions.js

@@ -216,6 +216,17 @@ describe("Twig.js Expressions ->", function() {
             test_template.render({a:false}).should.equal(true.toString());
             test_template.render({a:true}).should.equal(false.toString());
         });
+
+        it("should correctly cast arrays", function () {
+            var test_template = twig({data: '{{ a == true }}'});
+            test_template.render({a:['value']}).should.equal('true');
+            test_template.render({a:[]}).should.equal('false');
+        });
+
+        it("should correctly cast arrays in control structures", function () {
+            var test_template = twig({data: '{% if a is defined and a %}true{% else %}false{% endif %}'});
+            test_template.render({a:['value']}).should.equal('true');
+        });
     });
 
     describe("Other Operators ->", function() {