我的nightwatch.js自定义命令似乎不起作用

Question

下面是我的nightwatch.js测试脚本的摘录，我想将其创建到自定义命令中。

测试代码为；

"Page 1 Transission SEO Crawl paths are correct": function (browser) {
 // Transmission Solr Query Result Array
  var transmissionArray = ryanlinkstransmissionpage.Transmission.filter(val => typeof val === "string");
    transmissionArray.sort();
      // Transmission Facet Navigation
      browser.elements('xpath', '//a[contains(@href,"gearbox")]', function (transmissionFacetEntry) {
        var transmissionPageElement = [];
          transmissionFacetEntry.value.map(function(element) {
            browser.elementIdAttribute(element.ELEMENT, 'innerText', function(transmissionFacetEntryResult) {
              transmissionPageElement.push(transmissionFacetEntryResult.value);
                if (transmissionFacetEntry.value.length === transmissionPageElement.length) {
                  if (JSON.stringify(transmissionArray) === JSON.stringify(transmissionPageElement)) {
                    console.log("they are the same", transmissionArray, transmissionPageElement);
                    return true;
                  } else {
                      console.log("they are not the same", transmissionArray, transmissionPageElement);
                      return false;
                    }
                }
            });
          });
      });
},

当我运行包含此脚本的测试脚本时，测试成功并通过。

当我将其“转换”为自定义命令时，它看起来如下；

exports.command = function(ryanlinksproductionyearpage) {
  var yearArray = ryanlinksproductionyearpage.ProductionYear.filter(val => typeof val === "string");
    yearArray.sort();
      this
        .elements('xpath', '//a[contains(@href,"year")]', function (yearFacetEntry) {
          var yearPageElement = [];
            yearFacetEntry.value.map(function(element) {
              this.elementIdAttribute(element.ELEMENT, 'innerText', function(yearFacetEntryResult) {
                yearPageElement.push(yearFacetEntryResult.value);
                  if (yearFacetEntry.value.length === yearPageElement.length) {
                    if (JSON.stringify(yearArray) === JSON.stringify(yearPageElement)) {
                      console.log("they are the same", yearArray, yearPageElement);
                        return true;
                    } 
                          else {
                            console.log("they are not the same", yearArray, yearPageElement);
                              return false;
                          }
                  }
              });
            });
          }); 
  return this;
};

（请注意， ryanlinksproductionyearpage 已从测试脚本的另一部分中引用）。

我的测试脚本现在看起来像;

"Page 1 Year Plate SEO Crawl paths are correct": function (browser) {

   browser.cars_for_sale.make_level.ryan_links.yearPlateArrayComparison(ryanlinksproductionyearpage);
},

但是，我现在收到以下错误；

 ✖ TypeError: this.elementIdAttribute is not a function

我在自定义命令脚本中缺少明显/基本的东西吗？还是这是 elementIdAttribute 问题？

任何帮助将不胜感激。

谢谢