Chore: re-use code

Build/build-microsoft-cdn.ts

@@ -5,6 +5,7 @@ import { fetchRemoteTextByLine } from './lib/fetch-text-by-line';
 import { createTrie } from './lib/trie';
 import { SHARED_DESCRIPTION } from './lib/constants';
 import { createMemoizedPromise } from './lib/memo-promise';
+import { extractDomainsFromFelixDnsmasq } from './lib/parse-dnsmasq';
 
 const PROBE_DOMAINS = ['.microsoft.com', '.windows.net', '.windows.com', '.windowsupdate.com', '.windowssearch.com', '.office.net'];
 
@@ -26,8 +27,8 @@ export const getMicrosoftCdnRulesetPromise = createMemoizedPromise(async () => {
   // First trie is to find the microsoft domains that matches probe domains
   const trie = createTrie();
   for await (const line of await fetchRemoteTextByLine('https://raw.githubusercontent.com/felixonmars/dnsmasq-china-list/master/accelerated-domains.china.conf')) {
-    if (line.startsWith('server=/') && line.endsWith('/114.114.114.114')) {
-      const domain = line.slice(8, -16);
+    const domain = extractDomainsFromFelixDnsmasq(line);
+    if (domain) {
       trie.add(domain);
     }
   }

Build/lib/parse-dnsmasq.ts

@@ -6,14 +6,19 @@ const isDomainLoose = (domain: string): boolean => {
   return !!(!isIp && (isIcann || isPrivate));
 };
 
+export const extractDomainsFromFelixDnsmasq = (line: string): string | null => {
+  if (line.startsWith('server=/') && line.endsWith('/114.114.114.114')) {
+    return line.slice(8, -16);
+  }
+  return null;
+};
+
 export const parseFelixDnsmasq = async (url: string | URL): Promise<string[]> => {
   const res: string[] = [];
   for await (const line of await fetchRemoteTextByLine(url)) {
-    if (line.startsWith('server=/') && line.endsWith('/114.114.114.114')) {
-      const domain = line.slice(8, -16);
-      if (isDomainLoose(domain)) {
-        res.push(domain);
-      }
+    const domain = extractDomainsFromFelixDnsmasq(line);
+    if (domain && isDomainLoose(domain)) {
+      res.push(domain);
     }
   }
 

Build/validate-domestic.ts

@@ -3,12 +3,14 @@ import { parse } from 'csv-parse/sync';
 import { createTrie } from './lib/trie';
 import path from 'path';
 import { processLine } from './lib/process-line';
+import { extract } from 'tar-stream';
+import { extractDomainsFromFelixDnsmasq } from './lib/parse-dnsmasq';
 
 export const parseDomesticList = async () => {
   const set = new Set<string>();
   for await (const line of await fetchRemoteTextByLine('https://raw.githubusercontent.com/felixonmars/dnsmasq-china-list/master/accelerated-domains.china.conf')) {
-    if (line.startsWith('server=/') && line.endsWith('/114.114.114.114')) {
-      const domain = line.slice(8, -16);
+    const domain = extractDomainsFromFelixDnsmasq(line);
+    if (domain) {
       set.add(domain);
     }
   }