問(wèn)題描述

我不太明白 $ 和 $$ 命令的用途.我認(rèn)為它們只是by.css"的替代品，但為什么要使用 $$?

I don't really understand what the $ and $$ commands are for. I thought they are just a replacement for 'by.css' but why the $$?

<element id = "eId"></element>

我認(rèn)為，鑒于上述情況，這些將是等效的:

I thought, that given the above, these would be equivalent:

element(by.css('#eId'));

和

element($('#eId'));

但是，第一個(gè)有效，第二個(gè)無(wú)效.為什么，這三者有什么區(qū)別?

However, the first one works and the second doesn't. Why, what's the difference between the three?

docs 幫助不大.他們似乎暗示$"僅用于鏈接，例如element(by.css('#eId')).element($('#childId')); 或選擇第一個(gè)元素，然后選擇第一個(gè)元素內(nèi)的第二個(gè)元素."但是，我已經(jīng)看到使用 $ 來(lái)選擇第一個(gè)元素的示例.

The docs are of little help. They seem to imply that "$" is for chaining only, e.g. element(by.css('#eId')).element($('#childId')); or "Select the first element, and then select the second element within the first element.' However, I have seen examples with $ being used to select the first element.

不管怎樣，這三個(gè)(by.css、$ 和 $$)之間有什么區(qū)別?"的文字很多.

Anyway, that's a lot of text for "What are the differences between the three (by.css, $, and $$)?"

推薦答案

$ 和 $$ 只是方便的快捷方式.

$ and $$ are just convenient shortcuts.

$("selector") 是 element(by.css("selector")) 的替代品.

$$("selector") 是 element.all(by.css("selector")) 的替代品.

僅供參考，引用自 源代碼:p>

FYI, quote from the source code:

ElementFinder.prototype.$ = function(selector) {
  return this.element(webdriver.By.css(selector));
};

ElementArrayFinder.prototype.$$ = function(selector) {
  return this.all(webdriver.By.css(selector));
};

以及最初實(shí)現(xiàn)它的實(shí)際提交.

這篇關(guān)于量角器“by.css()"vs“$()"美元符號(hào)與“$$()"'亮閃閃'的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！