name: duk_new

proto: |
  void duk_new(duk_context *ctx, duk_idx_t nargs);

stack: |
  [ ... constructor! arg1! ...! argN! ] -> [ ... retval! ]

summary: |
  <p>Call a constructor function with <code>nargs</code> arguments
  (not counting the function itself).  The function and its arguments
  are replaced by a single return value.  An error thrown during the
  constructor call is not automatically caught.</p>

  <p>The target function <code>this</code> binding is set to a freshly
  created empty object.  If <code>constructor.prototype</code> is an
  object, the internal prototype of the new object is set to that
  value; otherwise the standard built-in <code>Object</code> prototype
  is used as the internal prototype.  The return value of the target
  function determines what the result of the constructor call is.
  If the constructor returns an object, it replaces the fresh empty object;
  otherwise the fresh empty object (possibly modified by the constructor)
  is returned.
  See <a href="http://www.ecma-international.org/ecma-262/5.1/#sec-13.2.2">[[Construct]]</a>.
  </p>

example: |
  /* Assume target function is already on stack at func_idx.
   * Equivalent to ECMAScript 'new func("foo", 123)'.
   */
  duk_idx_t func_idx = /* ... */;

  duk_dup(ctx, func_idx);
  duk_push_string(ctx, "foo");
  duk_push_int(ctx, 123);
  duk_new(ctx, 2);  /* [ ... func "foo" 123 ] -> [ ... res ] */
  printf("result is object: %d\n", (int) duk_is_object(ctx, -1));
  duk_pop(ctx);

tags:
  - object
  - call

seealso:
  - duk_pnew

introduced: 1.0.0