从url获取第一个和最后一个文件夹

Question

在Chrome扩展中，我有一个变量，它等于当前标签的url，比如currentUrl = tabs[0].url;。它得到一个类似于http://www.example.com/folder-1/folder-2/folder-3/index.html的url。

我想从这个url获取/folder/-1和/folder-3/。

我尝试了currentPath = currentUrl.substring(0, currentUrl.lastIndexOf("/"));，但是在这种方式下我只能得到完整的路径(http://www.example.com/folder1/folder2/folder3)

Answer 1

const arr = "http://www.example.com/folder-1/folder-2/folder-3/index.html".split("/");

然后arr[3]会给你文件夹-1，arr[arr.length - 2]会给你文件夹-3

Answer 2

要做到这一点，可能的方法之一是

splittedPath = ("http://www.example.com/folder1/folder2/folder3/index.html").split("/");
folder1 = splittedPath[3];
folderLast = splittedPath[splittedPath.length-2];

Answer 3

让我们测试更多的案例：

function getFirstAndLastFrom( URL ){

  const a = document.createElement("a");
  a.href = URL;
  let pathname = a.pathname.split("/");
  pathname.shift();  // Filter out first entry
  pathname.pop();    // Filter out last entry
  const first = pathname.length > 0 ? pathname[0] : null; // Do we have a first element?
  const last = pathname.length > 1 ? pathname[pathname.length-1] : null; // Do we have a last element?
  return { first, last };

}

const URL1 = "http://www.example.com/folder-1/folder-2/folder-3/index.html";
const URL2 = "http://example.com/folder-1/folder-2/folder-3/";
const URL3 = "http://www.example.com";
const URL4 = "http://subdomain.example.com/folder-1/folder-2/image.jpg";
const URL5 = "http://www.example.com/folder-1/image.jpg";
const URL6 = "http://www.google.com/";

{
  // Test case #1
  let { first, last } = getFirstAndLastFrom( URL1 );
  console.log( URL1, first, last );
}

{
  // Test case #2
 let { first, last } = getFirstAndLastFrom( URL2 );
  console.log( URL2, first, last );
}

{
  // Test case #3
  let { first, last } = getFirstAndLastFrom( URL3 );
  console.log( URL3, first, last );
}

{
  // Test case #4
  let { first, last } = getFirstAndLastFrom( URL4 );
  console.log( URL4, first, last );
}

{
  // Test case #5
  let { first, last } = getFirstAndLastFrom( URL5 );
  console.log( URL5, first, last );
}

{
  // Test case #6
  let { first, last } = getFirstAndLastFrom( URL6 );
  console.log( URL6, first, last );
}