Abort Controller for whois

kernel/bin/whois

@@ -165,13 +165,32 @@ function isLikelyDomain(s) {
 }
 
 async function fetchJson(fetchFn, url, timeoutMs) {
-  const ac = new AbortController()
-  const tid = setTimeout(() => ac.abort(), timeoutMs)
+  const AC =
+    typeof globalThis.AbortController === 'function'
+      ? globalThis.AbortController
+      : null
+
   let res
-  try {
-    res = await fetchFn(url, { method: 'GET', signal: ac.signal })
-  } finally {
-    clearTimeout(tid)
+  if (AC) {
+    const ac = new AC()
+    const tid = setTimeout(() => ac.abort(), timeoutMs)
+    try {
+      res = await fetchFn(url, { method: 'GET', signal: ac.signal })
+    } finally {
+      clearTimeout(tid)
+    }
+  } else {
+    /** Minimal hosts may lack AbortController; race fetch against a timer (does not cancel TCP). */
+    let tid
+    const abortErr = Object.assign(new Error('Aborted'), { name: 'AbortError' })
+    const deadline = new Promise((_, reject) => {
+      tid = setTimeout(() => reject(abortErr), timeoutMs)
+    })
+    try {
+      res = await Promise.race([fetchFn(url, { method: 'GET' }), deadline])
+    } finally {
+      if (tid) clearTimeout(tid)
+    }
   }
   if (!res || !res.ok) {
     const status = res ? `${res.status} ${res.statusText || ''}`.trim() : 'unknown'