我试图弄清楚如何从插件的JS代码中调用REST API自定义端点。这是我刚刚编写的一个示例插件的PHP代码，以显示我的问题。文件名为rest-api-sample.php:

<?php
/**
 * @link              https://www.virtualbit.it
 * @since             1.0.0
 * @package           Rest-API-Sample
 *
 * @wordpress-plugin
 * Plugin Name:       Rest API Sample
 * Plugin URI:        https://www.virtualbit.it/rest-api-sample
 * Description:       Just a code sample
 * Version:           1.0.4
 * Author:            Lucio Crusca
 * Author URI:        https://www.virtualbit.it
 * License:           GPL-2.0+
 * License URI:       http://www.gnu.org/licenses/gpl-2.0.txt
 * Text Domain:       rest-api-sample
 * Domain Path:       /languages
 */

class IESRestEndpoint 
{
  private $namespace = "ies/v1";
  public function __construct()  {
     add_action( \'rest_api_init\', array($this, \'registerRoutes\')); 
     add_action( \'wp_enqueue_scripts\', array($this, \'enqueue_scripts\'));
  }

  public function istermactive(WP_REST_Request $request)  {
    $result = true;
    return $result; // this is my controller.
  }

  public function registerRoutes()  {
    register_rest_route( $this->namespace, 
                         \'/istermactive/\', 
                          array(\'methods\' => \'GET\',
                                \'callback\' => array($this, \'istermactive\')
                               )
                       );
  }

  public function enqueue_scripts() {    
    $handle = "ies-rest-api";
    $jsfileurl = plugin_dir_url( __FILE__ ) . \'/ies.js\';
    wp_register_script($handle, $jsfileurl, array("underscore", "backbone", "wp-api"));    
    $local_data = array(\'apiRoot\' => get_rest_url(), "namespace" => $this->namespace);
    wp_localize_script($handle, "ies_rest", $local_data);
    wp_enqueue_script($handle);
  }  
}

$ies_endpoint = new IESRestEndpoint();

这是ies.js 代码：

(function( $ ) {
  \'use strict\';

  $(document).ready(function()
  {  
    wp.api.init({\'versionString\' : ies_rest.namespace,  \'apiRoot\': ies_rest.apiRoot}).done(function()
    { 
      wp.api.loadPromise.done(function () 
      {
        wp.api.namespace(ies_rest.namespace).istermactive().done(function (active)
        {
          alert(active);
        });
      });
    });    
  });

})( jQuery );

然而，WP 4.7.4/4.7.5中的这段JS代码在调用wp.api.init() 在它到达呼叫之前wp.api.loadPromise():

Uncaught TypeError: _.includes is not a function
    at wp-api.min.js?ver=4.7.4:1
    at Function.h.each.h.forEach (underscore-min.js?ver=4.7.4:1)
    at Object.wp.api.utils.decorateFromRoute (wp-api.min.js?ver=4.7.4:1)
    at wp-api.min.js?ver=4.7.4:1
    at Function.h.each.h.forEach (underscore-min.js?ver=4.7.4:1)
    at n.constructFromSchema (wp-api.min.js?ver=4.7.4:1)
    at n.<anonymous> (wp-api.min.js?ver=4.7.4:1)
    at n.<anonymous> (backbone.min.js?ver=1.2.3:1)
    at n.<anonymous> (underscore.min.js?ver=1.8.3:5)
    at _ (backbone.min.js?ver=1.2.3:1)

使用WP 4.8beta2的相同代码似乎至少在达到wp.api.namespace() 呼叫，我在哪里得到：

Uncaught TypeError: wp.api.namespace is not a function
    at Object.<anonymous> (https://www.virtualbit.it/wp-content/plugins/rest-api-sample//ies.js?ver=4.8-beta2:10:16)
    at i (https://www.virtualbit.it/wp-includes/js/jquery/jquery.js?ver=1.12.4:2:27449)
    at Object.add [as done] (https://www.virtualbit.it/wp-includes/js/jquery/jquery.js?ver=1.12.4:2:27748)
    at Object.<anonymous> (https://www.virtualbit.it/wp-content/plugins/rest-api-sample//ies.js?ver=4.8-beta2:8:26)
    at i (https://www.virtualbit.it/wp-includes/js/jquery/jquery.js?ver=1.12.4:2:27449)
    at Object.fireWith [as resolveWith] (https://www.virtualbit.it/wp-includes/js/jquery/jquery.js?ver=1.12.4:2:28213)
    at Object.e.(anonymous function) [as resolve] (https://www.virtualbit.it/wp-includes/js/jquery/jquery.js?ver=1.12.4:2:29192)
    at Object.<anonymous> (https://www.virtualbit.it/wp-includes/js/wp-api.min.js?ver=4.8-beta2:1:13404)
    at i (https://www.virtualbit.it/wp-includes/js/jquery/jquery.js?ver=1.12.4:2:27449)
    at Object.fireWith [as resolveWith] (https://www.virtualbit.it/wp-includes/js/jquery/jquery.js?ver=1.12.4:2:28213)

我的JS文件（ies.JS）甚至没有在4.7的堆栈跟踪中提到。x异常，而在4.8beta2中，这似乎是一个简单的语法错误，但我不知道应该如何调用我的端点。

我认为这可能是一个WP bug（可能是一个文档bug），于是我打开了一个bug报告。事实证明这不是一个WP错误，所以这个问题仍然需要答案，但Adam，谁回答了我的错误报告，给了我们some valuable informations.

至于建议birgire 很遗憾，我不知道如何使用QUnit 代码，也许你可以带我看看？

如果要尝试此示例插件，you can find it here, 而且，如果您感兴趣，可以在以下位置调试JS代码：my website homepage, 已安装此示例插件的位置（截至撰写本文时，WP版本为4.8beta2）。

wp_register_script($handle, $jsfileurl, array("underscore", "backbone", "wp-api"));