Add String::length method (#39)

src/string.cc

@@ -14,6 +14,10 @@ String* v8__String__NewFromUtf8(Isolate* isolate,
   return maybe_local_to_ptr(String::NewFromUtf8(isolate, data, type, length));
 }
 
+int v8__String__Length(const String& self) {
+  return self.Length();
+}
+
 int v8__String__Utf8Length(const String& self, Isolate* isolate) {
   return self.Utf8Length(isolate);
 }

src/string.rs

@@ -19,6 +19,8 @@ extern "C" {
     length: int,
   ) -> *mut String;
 
+  fn v8__String__Length(this: &String) -> int;
+
   fn v8__String__Utf8Length(this: &String, isolate: *mut CxxIsolate) -> int;
 
   fn v8__String__WriteUtf8(
@@ -78,6 +80,12 @@ impl String {
     }
   }
 
+  /// Returns the number of characters (UTF-16 code units) in this string.
+  pub fn length(&self) -> usize {
+    unsafe { v8__String__Length(self) as usize }
+  }
+
+  /// Returns the number of bytes in the UTF-8 encoded representation of this string.
   pub fn utf8_length(&self, isolate: &mut impl LockedIsolate) -> usize {
     unsafe { v8__String__Utf8Length(self, isolate.cxx_isolate()) as usize }
   }

tests/test_api.rs

@@ -90,6 +90,8 @@ fn test_string() {
     let reference = "Hello 🦕 world!";
     let local =
       v8::String::new(scope, reference, v8::NewStringType::Normal).unwrap();
+    assert_eq!(15, local.length());
+    assert_eq!(17, local.utf8_length(scope));
     assert_eq!(reference, local.to_rust_string_lossy(scope));
   });
 }