Check url and check if url is a domain or subdomain
I need to validate a url and check if the url is a domain or a subdomain.
I tried the solution, it works, but it failed in some cases.
function subDomain(url)
{
// IF THERE, REMOVE WHITE SPACE FROM BOTH ENDS
url = url.replace(new RegExp(/^\s+/),""); // START
url = url.replace(new RegExp(/\s+$/),""); // END
// IF FOUND, CONVERT BACK SLASHES TO FORWARD SLASHES
url = url.replace(new RegExp(/\\/g),"/");
// IF THERE, REMOVES 'http://', 'https://' or 'ftp://' FROM THE START
//url = url.replace(new RegExp(/^http\:\/\/|^https\:\/\/|^ftp\:\/\//i),"");
// IF THERE, REMOVES 'www.' FROM THE START OF THE STRING
url = url.replace(new RegExp(/^www\./i),"");
// REMOVE COMPLETE STRING FROM FIRST FORWARD SLASH ON
url = url.replace(new RegExp(/\/(.*)/),"");
// REMOVES '.??.??' OR '.???.??' FROM END - e.g. '.CO.UK', '.COM.AU'
if (url.match(new RegExp(/\.[a-z]{2,3}\.[a-z]{2}$/i))) {
url = url.replace(new RegExp(/\.[a-z]{2,3}\.[a-z]{2}$/i),"");
// REMOVES '.??' or '.???' or '.????' FROM END - e.g. '.US', '.COM', '.INFO'
} else if (url.match(new RegExp(/\.[a-z]{2,4}$/i))) {
url = url.replace(new RegExp(/\.[a-z]{2,4}$/i),"");
}
// CHECK TO SEE IF THERE IS A DOT '.' LEFT IN THE STRING
var subDomain = (url.match(new RegExp(/\./g))) ? true : false;
return(subDomain);
}
Results:
mydomain.com -> false subdomain.mydomain.com -> true mydomain.com. -> true
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1 answer
You can check this in a single regex like:
var isSubdomain = function(url) {
url = url || 'http://www.test-domain.com'; // just for the example
var regex = new RegExp(/^([a-z]+\:\/{2})?([\w-]+\.[\w-]+\.\w+)$/);
return !!url.match(regex); // make sure it returns boolean
}
console.log(isSubdomain("example.com"));
console.log(isSubdomain("http://example.com:4000"));
console.log(isSubdomain("www.example.com:4000"));
console.log(isSubdomain("https://www.example.com"));
console.log(isSubdomain("sub.example.com"));
console.log(isSubdomain("example.co.uk")); //it doesn't work on these very specific cases
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