Remove the string on the beginning of an URL

Question

I want to remove the " www. " part from the beginning of an URL string

For instance in these test cases:

eg www.test.com → test.com
eg www.testwww.com → testwww.com
eg testwww.com → testwww.com (if it doesn't exist)

Do I need to use Regexp or is there a smart function?

Answer 1

Depends on what you need, you have a couple of choices, you can do:

// this will replace the first occurrence of "www." and return "testwww.com"
"www.testwww.com".replace("www.", "");

// this will slice the first four characters and return "testwww.com"
"www.testwww.com".slice(4);

// this will replace the www. only if it is at the beginning
"www.testwww.com".replace(/^(www\.)/,"");

Answer 2

Yes, there is a RegExp but you don't need to use it or any "smart" function:

var url = "www.testwww.com";
var PREFIX = "www.";
if (url.startsWith(PREFIX)) {
  // PREFIX is exactly at the beginning
  url = url.slice(PREFIX.length);
}

Answer 3

如果字符串始终具有相同的格式，那么简单的substr()就足够了。

var newString = originalStrint.substr(4)

Answer 4

You can overload the String prototype with a removePrefix function:

String.prototype.removePrefix = function (prefix) {
    const hasPrefix = this.indexOf(prefix) === 0;
    return hasPrefix ? this.substr(prefix.length) : this.toString();
};

usage:

const domain = "www.test.com".removePrefix("www."); // test.com

Answer 5

Either manually, like

var str = "www.test.com",
    rmv = "www.";

str = str.slice( str.indexOf( rmv ) + rmv.length );

or just use .replace() :

str = str.replace( rmv, '' );

Answer 6

Try the following

var original = 'www.test.com';
var stripped = original.substring(4);

Answer 7

其他方式：

Regex.Replace(urlString, "www.(.+)", "$1");

Answer 8

const removePrefix = (value, prefix) =>
   value.startsWith(prefix) ? value.slice(prefix.length) : value;

Answer 9

您可以剪切 url 并使用 response.sendredirect(new url)，这会将您带到与新 url 相同的页面