feat: javascript helpers extension

fix #881

Author: alandefreitas

src/lib/Support/JavaScript.cpp

@@ -1015,6 +1015,14 @@ registerHelper(
         if (hasOptions)
             positionalArgs.pop_back();
 
+        auto allTruthy = [](std::vector<dom::Value> const& values)
+        {
+            return std::all_of(values.begin(), values.end(), [](dom::Value const& v)
+            {
+                return v.isTruthy();
+            });
+        };
+
         // Simple helpers: compute directly from positional args to avoid
         // Handlebars options coercing into unintended string results.
         if (simpleHelper)
@@ -1048,12 +1056,7 @@ registerHelper(
             }
             if (helperName == "and")
             {
-                if (positionalArgs.size() < 2)
-                    return dom::Value(false);
-                auto const& a = positionalArgs[0];
-                auto const& b = positionalArgs[1];
-                bool res = a.isBoolean() && b.isBoolean() && a.getBool() && b.getBool();
-                return dom::Value(res);
+                return dom::Value(allTruthy(positionalArgs));
             }
         }
 
@@ -1186,11 +1189,7 @@ registerHelper(
                 }
                 if (helperName == "and")
                 {
-                    if (positionalArgs.size() < 2) return dom::Value(false);
-                    auto const& a = positionalArgs[0];
-                    auto const& b = positionalArgs[1];
-                    bool res = a.isBoolean() && b.isBoolean() && a.getBool() && b.getBool();
-                    return dom::Value(res);
+                    return dom::Value(allTruthy(positionalArgs));
                 }
             }
         }

src/test/Support/JavaScript.cpp

@@ -1301,18 +1301,23 @@ struct JavaScript_test
                 });
             BOOST_TEST(hbs.render("{{concat 'a' 'b'}}") == "ab");
 
-            // Boolean
-            ensureHelper("and", "function(a, b) { return a && b; }",
+            // Boolean (truthiness)
+            ensureHelper("and", "function(...args) { args.pop(); return args.every(it => it); }",
                 [](dom::Array const& args, std::size_t count)
                 {
-                    if (count < 2)
-                        return dom::Value(false);
-                    auto const& a = args.get(0);
-                    auto const& b = args.get(1);
-                    bool res = a.isBoolean() && b.isBoolean() && a.getBool() && b.getBool();
+                    bool res = true;
+                    for (std::size_t i = 0; i < count; ++i)
+                    {
+                        res = res && args.get(i).isTruthy();
+                        if (!res)
+                            break;
+                    }
                     return dom::Value(res);
                 });
-            BOOST_TEST(hbs.render("{{and true true}}") == "true");
+            BOOST_TEST(hbs.render("{{and true 1 'x'}}") == "true");
+            BOOST_TEST(hbs.render("{{and true 0}}") == "false");
+            BOOST_TEST(hbs.render("{{and '' true}}") == "false");
+            BOOST_TEST(hbs.render("{{and 'a' 5}}") == "true");
 
             // Undefined
             ensureHelper("undef", "function() { return undefined; }",