Подключение JS без повторов?

Question

[Митя ТоДаСё]

Как проверить/исключить повторное подключение JS файла?
Спасибо!

Answer 1

[Евгений Безымянников]

function include_once( filename ) { 
    var cur_file = {};
    cur_file[window.location.href] = 1;
    if (!window.php_js) window.php_js = {};
    if (!window.php_js.includes) window.php_js.includes = cur_file;
    if (!window.php_js.includes[filename]) {
        return this.include(filename);
    } else{
        return window.php_js.includes[filename];
    }
}

Примеры:
include_once('/js/my1.js');

Comments

[Митя ТоДаСё]

function include_once( filename ) { 
    var cur_file = {};
    cur_file[window.location.href] = 1;
    if (!window.php_js) window.php_js = {};
    if (!window.php_js.includes) window.php_js.includes = cur_file;
    if (!window.php_js.includes[filename]) {
        return this.include(filename);
    } else{
        return window.php_js.includes[filename];
    }
}

 $(function(){ 
    include_once('https://site.ru/js/preloader.js');
    include_once('https://site.ru/js/functions.js');
    include_once('https://site.ru/js/getURL.js');
});

но получаю ошибку

javascript.js:11 Uncaught TypeError: this.include is not a function

jQuery v2.2.4