fix: don't add listeners to the same signal more than once

lib/api/abort-signal.js

@@ -1,7 +1,7 @@
 const { addAbortListener } = require('../core/util')
 const { RequestAbortedError } = require('../core/errors')
 
-const kListener = Symbol('kListener')
+const kListenersList = Symbol('kListenersList')
 const kSignal = Symbol('kSignal')
 
 function abort (self) {
@@ -13,11 +13,32 @@ function abort (self) {
   removeSignal(self)
 }
 
+function handleAbort (signal) {
+  for (const listener of signal[kListenersList]) {
+    abort(listener)
+  }
+  clearListeners(signal)
+}
+
+function clearListeners (signal) {
+  if (!signal[kListenersList]) {
+    return
+  }
+  if ('removeEventListener' in signal) {
+    signal.removeEventListener('abort', handleAbort)
+  } else {
+    signal.removeListener('abort', handleAbort)
+  }
+  if (signal[kListenersList].size !== 0) {
+    signal[kListenersList].clear()
+  }
+  signal[kListenersList] = null
+}
+
 function addSignal (self, signal) {
   self.reason = null
 
   self[kSignal] = null
-  self[kListener] = null
 
   if (!signal) {
     return
@@ -29,26 +50,27 @@ function addSignal (self, signal) {
   }
 
   self[kSignal] = signal
-  self[kListener] = () => {
-    abort(self)
+
+  if (!signal[kListenersList]) {
+    signal[kListenersList] = new Set()
+    addAbortListener(signal, handleAbort)
   }
 
-  addAbortListener(self[kSignal], self[kListener])
+  signal[kListenersList].add(self)
 }
 
 function removeSignal (self) {
   if (!self[kSignal]) {
     return
   }
 
-  if ('removeEventListener' in self[kSignal]) {
-    self[kSignal].removeEventListener('abort', self[kListener])
-  } else {
-    self[kSignal].removeListener('abort', self[kListener])
+  self[kSignal][kListenersList].delete(self)
+
+  if (self[kSignal][kListenersList].size === 0) {
+    clearListeners(self[kSignal])
   }
 
   self[kSignal] = null
-  self[kListener] = null
 }
 
 module.exports = {