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@Sinequanonh
Created November 22, 2022 23:11
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is-url.js
/**
* Expose `isUrl`.
*/
module.exports = isUrl;
/**
* RegExps.
* A URL must match #1 and then at least one of #2/#3.
* Use two levels of REs to avoid REDOS.
*/
var protocolAndDomainRE = /^(?:\w+:)?\/\/(\S+)$/;
var localhostDomainRE = /^localhost[\:?\d]*(?:[^\:?\d]\S*)?$/
var nonLocalhostDomainRE = /^[^\s\.]+\.\S{2,}$/;
/**
* Loosely validate a URL `string`.
*
* @param {String} string
* @return {Boolean}
*/
function isUrl(string){
if (typeof string !== 'string') {
return false;
}
var match = string.match(protocolAndDomainRE);
if (!match) {
return false;
}
var everythingAfterProtocol = match[1];
if (!everythingAfterProtocol) {
return false;
}
if (localhostDomainRE.test(everythingAfterProtocol) ||
nonLocalhostDomainRE.test(everythingAfterProtocol)) {
return true;
}
return false;
}
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