Add len helper

src/helpers/helper_boolean.rs → src/helpers/helper_extras.rs

@@ -1,4 +1,5 @@
 //! Helpers for boolean operations
+use serde_json::Value as Json;
 
 use crate::json::value::JsonTruthy;
 
@@ -11,6 +12,14 @@ handlebars_helper!(lte: |x: i64, y: i64| x <= y);
 handlebars_helper!(and: |x: Json, y: Json| x.is_truthy(false) && y.is_truthy(false));
 handlebars_helper!(or: |x: Json, y: Json| x.is_truthy(false) || y.is_truthy(false));
 handlebars_helper!(not: |x: Json| !x.is_truthy(false));
+handlebars_helper!(len: |x: Json| {
+    match x {
+        Json::Array(a) => a.len(),
+        Json::Object(m) => m.len(),
+        Json::String(s) => s.len(),
+        _ => 0
+    }
+});
 
 #[cfg(test)]
 mod test_conditions {
@@ -75,4 +84,29 @@ mod test_conditions {
             .unwrap();
         assert_eq!(&result, "ipsum");
     }
+
+    #[test]
+    fn test_len() {
+        let handlebars = crate::Handlebars::new();
+
+        let result = handlebars
+            .render_template("{{len value}}", &json!({"value": [1,2,3]}))
+            .unwrap();
+        assert_eq!(&result, "3");
+
+        let result = handlebars
+            .render_template("{{len value}}", &json!({"value": {"a" :1, "b": 2}}))
+            .unwrap();
+        assert_eq!(&result, "2");
+
+        let result = handlebars
+            .render_template("{{len value}}", &json!({"value": "tomcat"}))
+            .unwrap();
+        assert_eq!(&result, "6");
+
+        let result = handlebars
+            .render_template("{{len value}}", &json!({"value": 3}))
+            .unwrap();
+        assert_eq!(&result, "0");
+    }
 }

src/helpers/mod.rs

@@ -132,8 +132,8 @@ impl<
 }
 
 mod block_util;
-pub(crate) mod helper_boolean;
 mod helper_each;
+pub(crate) mod helper_extras;
 mod helper_if;
 mod helper_log;
 mod helper_lookup;

src/registry.rs

@@ -138,15 +138,16 @@ impl<'reg> Registry<'reg> {
         self.register_helper("raw", Box::new(helpers::RAW_HELPER));
         self.register_helper("log", Box::new(helpers::LOG_HELPER));
 
-        self.register_helper("eq", Box::new(helpers::helper_boolean::eq));
-        self.register_helper("ne", Box::new(helpers::helper_boolean::ne));
-        self.register_helper("gt", Box::new(helpers::helper_boolean::gt));
-        self.register_helper("gte", Box::new(helpers::helper_boolean::gte));
-        self.register_helper("lt", Box::new(helpers::helper_boolean::lt));
-        self.register_helper("lte", Box::new(helpers::helper_boolean::lte));
-        self.register_helper("and", Box::new(helpers::helper_boolean::and));
-        self.register_helper("or", Box::new(helpers::helper_boolean::or));
-        self.register_helper("not", Box::new(helpers::helper_boolean::not));
+        self.register_helper("eq", Box::new(helpers::helper_extras::eq));
+        self.register_helper("ne", Box::new(helpers::helper_extras::ne));
+        self.register_helper("gt", Box::new(helpers::helper_extras::gt));
+        self.register_helper("gte", Box::new(helpers::helper_extras::gte));
+        self.register_helper("lt", Box::new(helpers::helper_extras::lt));
+        self.register_helper("lte", Box::new(helpers::helper_extras::lte));
+        self.register_helper("and", Box::new(helpers::helper_extras::and));
+        self.register_helper("or", Box::new(helpers::helper_extras::or));
+        self.register_helper("not", Box::new(helpers::helper_extras::not));
+        self.register_helper("len", Box::new(helpers::helper_extras::len));
 
         self.register_decorator("inline", Box::new(decorators::INLINE_DECORATOR));
         self
@@ -612,7 +613,7 @@ mod test {
 
         // built-in helpers plus 1
         let num_helpers = 7;
-        let num_boolean_helpers = 9; // stuff like gt and lte
+        let num_boolean_helpers = 10; // stuff like gt and lte
         let num_custom_helpers = 1; // dummy from above
         assert_eq!(
             r.helpers.len(),