Detailed explanation of window.location object in JS (cheat sheet)

If you want to get the URL information of the site, then the window.location object is suitable for you! Use its properties to get information about the current page address, or use its methods to do some page redirection or refresh

window.location.origin    → '"https://segmentfault.com'
               .protocol  → 'https:'
               .host      → 'segmentfault.com'
               .hostname  → 'segmentfault.com'
               .port      → ''
               .pathname  → '/search'
               .search    → '?q=前端小智'
               .hash      → '#2'
               .href      → 'https://segmentfault.com/search?q=前端小智#2'

window.location.assign('url')
               .replace('url')
               .reload()
               .toString()

window.location property

window.location	Return value
.origin	Site main address (protocol host name port )
.protocol	Protocol architecture (http: or htts:)
.host	Domain name port
.port	Port
.pathname	The path followed by '/' on the first page
.search	? The query string followed
.hash	Part starting from
#.href	Full URL

The difference between host and hostname

In the above example, you may notice that host and hostnameReturn the same value. So why these properties. Well, it's about the port number, so let's take a look.

URL without port

https://segmentfault.com/search

window.location.host; // 'segmentfault.com'
window.location.hostname; // 'segmentfault.com'

window.location.port; // ''

URL with port

##https://segmentfault.com/search"8080

window.location.host; // 'segmentfault.com:8080'
window.location.hostname; // 'segmentfault.com'

window.location.port; // '8080'

Therefore,

host will include the port number, while hostname will return only the host name.

How to change URL properties

Not only can we call the location` attribute to retrieve URL information, we can also use it to set new properties and change the URL.

// 开始 'https://segmentfault.com/'

window.location.pathname = '/tidbits'; // 设置 pathname

// 结果 'https://segmentfault.com/tidbits'

Here is the complete list of properties you can change

// 事例
window.location.protocol = 'https'
               .host     = 'localhost:8080'
               .hostname = 'localhost'
               .port     = '8080'
               .pathname = 'path'
               .search   = 'query string' // (这里不用写 `?`)
               .hash     = 'hash' // (这里不用写 `#`)
               .href     = 'url'

The only property that cannot be set is

window.location.origin, which is read-only.

Location object

window.location Returns a Location object. It gives us information about the current address of the page. But we can also access the Location object in several ways.

window.location          → Location
window.document.location → Location
document.location        → Location
location                 → Location

The reason we do this is that these are global variables in our browser.

window.location vs location

The above four properties all point to the same

Location object. I personally prefer window.location and would actually avoid using location. Mainly because location looks like a normal variable, and we may sometimes accidentally name it as a variable, which will override the global variable. For example:

// https://www.samanthaming.com

location.protocol; // 'https'

function localFile() {
  const location = '/sam';

  return location.protocol;
  //  undefined
  //    b/c local "location" has override the global variable
}

I think most developers know that

window is a global variable. That way it's less likely to cause confusion. To be honest, I didn't know location## until I wrote this article # is a global variable. It is recommended that you use window.location instead of other writing methods.

window.location method

Method##.assign()Load a new Document.replace()Replace the current document with a new one.reload()Reload the current page.reload()Returned URL

window.location.toString

根据 MDN :

此方法返回 URL 的 USVString，它是 Location.href 的只读版本。

换句话说，我们可以这样得到  href  的值：

// https://www.samanthaming.com

window.location.href; // https://www.samanthaming.com
window.location.toString(); // https://www.samanthaming.com

assign vs replace

这两种方法都是重定向或导航到另一个URL。区别在于assign 是将当前页面保存在历史记录中，因此用户可以使用“后退”按钮导航到该页面。而使用replace方法时，不会保存它。让我们来看一个例子。

Assign

1. 打开一个新的空白页
2. 输入 www.samanthaming.com (当前页)

3. 使用 `window.location.assign('https://www.w3schools.com')` 载入新页面
4. 按 "返回上一页"
5. 返回到了 ???? www.samanthaming.com

Replace

1. 打开一个新的空白页
2. 输入 www.samanthaming.com (当前页)

3. 使用 `window.location.assign('https://www.w3schools.com')` 载入新页面
4. 按 "返回上一页"
5. 返回到一个空白页

如何让页面重定向

如何重定向到另一个页面，有3种方法。

window.location.href = 'https://www.samanthaming.com';

window.location.assign('https://www.samanthaming.com');

window.location.replace('https://www.samanthaming.com');

replace vs assign vs href

这三个都可以重定向，区别在于浏览器的历史记录。href和assign 会把当前页面保存在历史记录中，而replace则不会。因此，如果你想创建一种导航无法回到原始页面的体验，请使用replace????

现在的问题是href与assign。我更喜欢assign，因为它是一种方法，因此感觉好像我正在执行一些操作。还有一个额外的好处是它更易于测试。我已经编写了许多Jest测试，因此通过使用一种方法，它使其更易于模拟。

window.location.assign = jest.fn();

myUrlUpdateFunction();

expect(window.location.assign).toBeCalledWith('http://my.url');

最终希望备忘单，希望能对你有所帮助，在需要的时候，能快速给你带来答案。谢谢大家的观看。

英文原文地址：https://morioh.com/p/b444d291bdfb

作者：Samantha Ming

译者：前端小智

更多编程相关知识，请访问：编程入门！！

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