javascript - 从主机名获取域名扩展

Question

使用正则表达式从主机名中提取域名扩展(例如 .com)而不是域名(例如 google.com)。

输入=>输出

www.google.com => .com

google.com => .com

google.co.uk => .co.uk

www.google.co.uk => .co.uk

sub.google.co.uk => .co.uk

不是 Get domain name without subdomains using JavaScript? 的重复项

Answer 1

您可以手动检查 list of country domains然后是出现在其前面的前面的域段。

即:<other>.<topLevelDomain>.[optionalCountryCode]

示例如下:

function getTopDomain(domain) {
  const topDomainExpression = /\w+((\.[a-z]{2,3})(\.(ad|ae|af|ag|ai|al|am|ao|aq|ar|as|at|au|aw|ax|az|ba|bb|bd|be|bf|bg|bh|bi|bj|bl|bm|bn|bo|bq|br|bs|bt|bv|bw|by|bz|ca|cc|cd|cf|cg|ch|ci|ck|cl|cm|cn|co|cr|cu|cv|cw|cx|cy|cz|de|dj|dk|dm|do|dz|ec|ee|eg|er|es|et|fi|fj|fk|fm|fo|fr|ga|gb|gd|ge|gf|gg|gh|gi|gl|gm|gn|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|im|in|io|iq|ir|is|it|je|jm|jo|jp|ke|kg|kh|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly|ma|mc|md|me|mf|mg|mh|mk|ml|mm|mn|mo|mp|mq|mr|ms|mt|mu|mv|mw|mx|my|mz|na|nc|ne|nf|ng|ni|nl|no|np|nr|nu|nz|om|pa|pe|pf|pg|ph|pk|pl|pm|pn|pr|ps|pt|pw|py|qa|re|ro|rs|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|sk|sl|sm|sn|so|sr|ss|st|sv|sx|sy|sz|tc|td|tf|tg|th|tj|tk|tl|tm|tn|to|tr|tt|tv|tw|tz|ua|ug|uk|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|ye|yt|za|zm|zw))?)$/i;
  const match = topDomainExpression.exec(domain);
  
  return match[1];
}

function test(input, expectedOutput) {
  const output = getTopDomain(input);
  console.log(`${output === expectedOutput ? 'PASS' : 'FAIL'}: ${input} (expected: ${expectedOutput}, output: ${output})`);
}

test('www.google.com', '.com');
test('google.com', '.com');
test('google.co.uk', '.co.uk');
test('www.google.co.uk', '.co.uk');
test('sub.google.co.uk', '.co.uk');
test('bit.ly', '.ly');
test('something.co.ly', '.co.ly');