Introduce new.target C api (#3522)

Added new "jerry_get_new_target" API function and updated the unit test. JerryScript-DCO-1.0-Signed-off-by: Peter Gal pgal.u-szeged@partner.samsung.com
2020-01-18 10:58:33 +01:00
parent f46d061d19
commit 24af089643
4 changed files with 164 additions and 13 deletions
@@ -7655,6 +7655,138 @@ main (void)

 - [jerry_create_external_function](#jerry_create_external_function)

+## jerry_get_new_target
+
+**Summary**
+
+Returns the current "new.target" JavaScript function at the call site.
+
+If used outside of a native C function it will return "undefined" value.
+
+*Notes*:
+- Returned value must be freed with [jerry_release_value](#jerry_release_value) when it
+is no longer needed.
+- This feature depends on build option (`JERRY_ES2015`) and can be checked
+  in runtime with the `JERRY_FEATURE_SYMBOL` feature enum value (as symbols are enabled in case of ES2015),
+  see: [jerry_is_feature_enabled](#jerry_is_feature_enabled).
+- If the ES2015 mode is not enabled this method will always return the "undefined" value.
+
+**Prototype**
+
+```c
+jerry_value_t
+jerry_get_new_target (void);
+```
+- return
+  - "undefined" - if at the call site it was not a constructor call.
+  - function object - if the current call site is in a constructor call.
+
+*New in version 2.2*.
+
+**Example 1**
+
+[doctest]: # (name="02.API-REFERENCE-jsnewtarget-01.c")
+
+```c
+#include <stdio.h>
+#include <string.h>
+#include <jerryscript.h>
+
+static jerry_value_t
+demo_handler (const jerry_value_t func_obj_val,
+              const jerry_value_t this_val,
+              const jerry_value_t args_p[],
+              const jerry_length_t args_cnt)
+{
+  jerry_value_t new_target = jerry_get_new_target ();
+
+  /* new_target is the "demo" JS function object */
+  if (jerry_value_get_type (new_target) == JERRY_TYPE_FUNCTION)
+  {
+    printf ("This is a construct call\r\n");
+  }
+
+  jerry_release_value (new_target);
+
+  return jerry_create_undefined ();
+}
+
+int
+main (int argc, char** argv)
+{
+  jerry_init (JERRY_INIT_EMPTY);
+
+  jerry_value_t function_val = jerry_create_external_function (demo_handler);
+
+  jerry_value_t ret_val = jerry_construct_object (function_val, NULL, 0);
+
+  jerry_release_value (ret_val);
+  jerry_release_value (function_val);
+
+  jerry_cleanup ();
+  return 0;
+}
+```
+
+**Example 2**
+
+[doctest]: # (name="02.API-REFERENCE-jsnewtarget-02.c")
+
+```c
+#include <stdio.h>
+#include <string.h>
+#include <jerryscript.h>
+
+static jerry_value_t
+demo_handler (const jerry_value_t func_obj_val,
+              const jerry_value_t this_val,
+              const jerry_value_t args_p[],
+              const jerry_length_t args_cnt)
+{
+  jerry_value_t new_target = jerry_get_new_target ();
+
+  /* new_target is a JS function object */
+  if (jerry_value_get_type (new_target) == JERRY_TYPE_FUNCTION)
+  {
+    printf ("This is a construct call\r\n");
+  }
+
+  jerry_release_value (new_target);
+
+  return jerry_create_undefined ();
+}
+
+int
+main (int argc, char** argv)
+{
+  jerry_init (JERRY_INIT_EMPTY);
+
+  /* register C method */
+  jerry_value_t global_obj_val = jerry_get_global_object ();
+  jerry_value_t function_val = jerry_create_external_function (demo_handler);
+  jerry_value_t function_name_val = jerry_create_string ((const jerry_char_t *) "demo");
+  jerry_value_t result_val = jerry_set_property (global_obj_val, function_name_val, function_val);
+  jerry_release_value (result_val);
+  jerry_release_value (function_name_val);
+  jerry_release_value (function_val);
+  jerry_release_value (global_obj_val);
+
+  /* Invoke C method via JS */
+  const char *src = "new demo ()";
+  jerry_value_t ret_val = jerry_eval ((const jerry_char_t *) src,
+                                      strlen (src),
+                                      JERRY_PARSE_NO_OPTS);
+
+  jerry_release_value (ret_val);
+
+  jerry_cleanup ();
+  return 0;
+}
+```
+
+**See also**
+
+- [jerry_construct_object](#jerry_construct_object)

 # ArrayBuffer and TypedArray functions