How to add a custom JS file to the frontend of PrestaShop

prestashop_head_js.php

<?php
public function install()
{
    // Hook registration needs to go in the install function of your module
    if ($this->registerHook('displayHeader')) {
        return true;
    }

    return false;
}

/**
 * Function called by displayHeader hook
 */
public function hookDisplayHeader()
{
    // Add the path to your JS file
    // path_to_modules/this_module_name/path_to_js_file.js
    $this->context->controller->addJS(_MODULE_DIR_ . $this->name . '/file_name.js');

    // Optionally add some custom HTML to the HEAD tag
    // path_to_this_file/path_to_template.tpl
    //return $this->display(__FILE__, 'template_file.tpl');

    return false;
}