node_modules/tldts-core/src/lookup/fast-path.ts

import { IPublicSuffix, ISuffixLookupOptions } from './interface';

export default function (
  hostname: string,
  options: ISuffixLookupOptions,
  out: IPublicSuffix,
): boolean {
  // Fast path for very popular suffixes; this allows to by-pass lookup
  // completely as well as any extra allocation or string manipulation.
  if (!options.allowPrivateDomains && hostname.length > 3) {
    const last: number = hostname.length - 1;
    const c3: number = hostname.charCodeAt(last);
    const c2: number = hostname.charCodeAt(last - 1);
    const c1: number = hostname.charCodeAt(last - 2);
    const c0: number = hostname.charCodeAt(last - 3);

    if (
      c3 === 109 /* 'm' */ &&
      c2 === 111 /* 'o' */ &&
      c1 === 99 /* 'c' */ &&
      c0 === 46 /* '.' */
    ) {
      out.isIcann = true;
      out.isPrivate = false;
      out.publicSuffix = 'com';
      return true;
    } else if (
      c3 === 103 /* 'g' */ &&
      c2 === 114 /* 'r' */ &&
      c1 === 111 /* 'o' */ &&
      c0 === 46 /* '.' */
    ) {
      out.isIcann = true;
      out.isPrivate = false;
      out.publicSuffix = 'org';
      return true;
    } else if (
      c3 === 117 /* 'u' */ &&
      c2 === 100 /* 'd' */ &&
      c1 === 101 /* 'e' */ &&
      c0 === 46 /* '.' */
    ) {
      out.isIcann = true;
      out.isPrivate = false;
      out.publicSuffix = 'edu';
      return true;
    } else if (
      c3 === 118 /* 'v' */ &&
      c2 === 111 /* 'o' */ &&
      c1 === 103 /* 'g' */ &&
      c0 === 46 /* '.' */
    ) {
      out.isIcann = true;
      out.isPrivate = false;
      out.publicSuffix = 'gov';
      return true;
    } else if (
      c3 === 116 /* 't' */ &&
      c2 === 101 /* 'e' */ &&
      c1 === 110 /* 'n' */ &&
      c0 === 46 /* '.' */
    ) {
      out.isIcann = true;
      out.isPrivate = false;
      out.publicSuffix = 'net';
      return true;
    } else if (
      c3 === 101 /* 'e' */ &&
      c2 === 100 /* 'd' */ &&
      c1 === 46 /* '.' */
    ) {
      out.isIcann = true;
      out.isPrivate = false;
      out.publicSuffix = 'de';
      return true;
    }
  }

  return false;
}