Add column into Javascript function in .js file -

i have add line of code existing js function. cannot add right into, because can interfere future updates of .js file. have add .js file.

part of code want add line is:

(function($) {  if (typeof _wpcf7 == 'undefined' || _wpcf7 === null) {     _wpcf7 = {}; }  _wpcf7 = $.extend({     cached: 0 }, _wpcf7);  $.fn.wpcf7initform = function() {     this.ajaxform({         beforesubmit: function(arr, $form, options) {             $form.wpcf7clearresponseoutput();             $form.find('[aria-invalid]').attr('aria-invalid', 'false');             $form.find('img.ajax-loader').css({ visibility: 'visible' });         }, 

and line want add is:

$form.find('input.wpcf7-submit').val('sending'); 

the part want add should right under:

$form.find('img.ajax-loader').css({ visibility: 'visible' }); 

how can achive it?

sorry poor language, , in advance answers :)