js判断是网址

function isValidUrl(url) {
  const pattern = new RegExp('^(https?:\\/\\/)?'+ // protocol
    '((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.?)+[a-z]{2,}|'+ // domain name
    '((\\d{1,3}\\.){3}\\d{1,3}))'+ // OR ip (v4) address
    '(\\:\\d+)?(\\/[-a-z\\d%_.~+]*)*'+ // port and path
    '(\\?[;&a-z\\d%_.~+=-]*)?'+ // query string
    '(\\#[-a-z\\d_]*)?$','i'); // fragment locator
  return !!pattern.test(url);
}

console.log(isValidUrl("https://www.example.com")); // true
console.log(isValidUrl("ftp://example.com")); // false

function isValidUrl(url) {
  try {
    new URL(url);
    return true;
  } catch (err) {
    return false;
  }
}

console.log(isValidUrl("https://www.example.com")); // true
console.log(isValidUrl("invalid-url")); // false

const validator = require('validator');

console.log(validator.isURL("https://www.example.com")); // true
console.log(validator.isURL("ftp://example.com")); // false