laravel5.8 开箱即用辅助函数

https://learnku.com/docs/laravel/5.8/helpers/3919

好多5.5中的helper封装的方法，5.9将被弃用

文件路径: xx/vendor/laravel/framework/src/Illuminate/Support/helpers.php

if (! function_exists('array_add')) {
    /**
     * Add an element to an array using "dot" notation if it doesn't exist.
     *
     * @param  array   $array
     * @param  string  $key
     * @param  mixed   $value
     * @return array
     *
     * @deprecated Arr::add() should be used directly instead. Will be removed in Laravel 5.9.
     * 应该直接使用。将被删除在Laravel 5.9
     */
    function array_add($array, $key, $value)
    {
        return Arr::add($array, $key, $value);
    }
}