const packagePathnameFormat = /^\/((?:@[^/@]+\/)?[^/@]+)(?:@([^/]+))?(\/.*)?$/;

export default function parsePackagePathname(pathname) {

try {

pathname = decodeURIComponent(pathname);

} catch (error) {

return null;

}

const match = packagePathnameFormat.exec(pathname);

// Disallow invalid pathnames.

if (match == null) return null;

const packageName = match[1];

const packageVersion = match[2] || 'latest';

const filename = (match[3] || '').replace(/\/\/+/g, '/');

return {

// If the pathname is /@scope/name@version/file.js:

packageName, // @scope/name

packageVersion, // version

packageSpec: `${packageName}@${packageVersion}`, // @scope/name@version

filename // /file.js

};

}