Question

我有下面的代码，我在一个内联函数中将值加载到数组usageCategory中。但是，当我尝试在此函数之外打印值时，不会打印任何内容。

ItemsPresenter

我在这里做错了什么？我如何在内联函数之外访问这些数组值？任何帮助将不胜感激。

Answer 1

使用ElementArrayFinder.prototype.map

这可能是使用.map函数的好时机，因为它将把ElementArrayFinder对象转换为您创建的对象列表。 http://www.protractortest.org/#/api?view=ElementArrayFinder.prototype.map在量角器示例中（在链接中），地图返回对象列表。对于您的情况，您需要等待该元素的文本，然后在地图回调函数中将其返回。

async getAllUsageCategoryElements() {
    // extract all the droplist elements and put into an array so that I can validate them from another page.
    const spans = this.addAdditionalCostDialogue.usageCategoryDropListContainer
        .all(by.tagName('li')).all(by.tagName("span"));
    // Map over an ElementArrayFinder to get a list of returned items from
    // map operation. In this case, we are returning a list of strings
    const usageCategories = await spans.map(async (el) => {
      const text = await el.getText();
      // console.log(`printing directly ${text}`);
      return text;
    });

    console.log("Size of the array is " + usageCategories.length);
    for (let usageCategory of usageCategories) {
      console.log(`printing text ${usageCategory}`);
    }
}

Answer 2

您的代码中有两个问题：

1）usageCategory是局部变量，不是函数getAllUsageCategoryElements的属性，因此不能使用that.usageCategory.push(text);，而只能使用usageCategory.push(text);

2）getText()是异步API，以下同步代码将在getText()之前执行，
，因此 usageCategory.length 为 0 。您需要将这些同步代码放在then()之后的下一个getText()中，以使其在getText()之后执行。

console.log("Size of the array is " + usageCategories.length);
for (let usageCategory of usageCategories) {
  console.log(`printing text ${usageCategory}`);
}

更正的代码：

getAllUsageCategoryElements(){

    var usageCategory: string[] =  [];


    // extract all the droplist elements and put into an array so that I can validate them from another page.
    this.addAdditionalCostDialogue
        .usageCategoryDropListContainer
        .all(by.tagName('li'))
        .all(by.tagName("span"))
        .each(function (element, index) {

            element.getText().then(function (text){
                //console.log("printing directly " + text);
                // the above code works fine and prints all the drop list contains but when I try to add it to an array
                usageCategory.push(text);
            })
    })

    .then(function(){

        console.log("Size of the array is " + usageCategory.length);

        usageCategory.forEach(element => {
            console.log("Printing text " + element);
        }); 

        return usageCategory;
    });

}

内联函数中无法访问Typescript方法变量

2 个答案:

使用ElementArrayFinder.prototype.map