fbsample_jsaddvariable.php

<?php
/**
 * 2007-2018 Frédéric BENOIST
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Academic Free License (AFL 3.0)
 * that is bundled with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://opensource.org/licenses/afl-3.0.php
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@prestashop.com so we can send you a copy immediately.
 *
 *  @author    Frédéric BENOIST
 *  @copyright 2013-2018 Frédéric BENOIST <https://www.fbenoist.com/>
 *  @license   http://opensource.org/licenses/afl-3.0.php  Academic Free License (AFL 3.0)
 */

if (!defined('_PS_VERSION_')) {
     exit;
}

class FbSample_JsAddVariable extends Module
{
    public function __construct()
    {
        $this->name = 'fbsample_jsaddvariable';
        $this->author = 'Frédéric BENOIST';
        $this->version = '1.0.0';
        $this->need_instance = 0;
        $this->bootstrap = true;
        $this->tab = 'others';
        parent::__construct();

        $this->displayName = $this->l('Add value in prestashop JS var');
        $this->ps_versions_compliancy = array('min' => '1.7.3.1', 'max' => _PS_VERSION_);
        $this->description = $this->l('Add custom value in prestashop JavaSript var.');
    }

    public function install()
    {
        return parent::install()
            && $this->registerHook('actionBuildFrontEndObject');
    }

    public function hookActionBuildFrontEndObject(&$params)
    {
        $params['obj']['my_custom_data'] = 'my custom value';
    }
}