feat(adapter): add fetch adapter; (#6371)

lib/helpers/composeSignals.js

@@ -0,0 +1,46 @@
+import CanceledError from "../cancel/CanceledError.js";
+import AxiosError from "../core/AxiosError.js";
+
+const composeSignals = (signals, timeout) => {
+  let controller = new AbortController();
+
+  let aborted;
+
+  const onabort = function (cancel) {
+    if (!aborted) {
+      aborted = true;
+      unsubscribe();
+      const err = cancel instanceof Error ? cancel : this.reason;
+      controller.abort(err instanceof AxiosError ? err : new CanceledError(err instanceof Error ? err.message : err));
+    }
+  }
+
+  let timer = timeout && setTimeout(() => {
+    onabort(new AxiosError(`timeout ${timeout} of ms exceeded`, AxiosError.ETIMEDOUT))
+  }, timeout)
+
+  const unsubscribe = () => {
+    if (signals) {
+      timer && clearTimeout(timer);
+      timer = null;
+      signals.forEach(signal => {
+        signal &&
+        (signal.removeEventListener ? signal.removeEventListener('abort', onabort) : signal.unsubscribe(onabort));
+      });
+      signals = null;
+    }
+  }
+
+  signals.forEach((signal) => signal && signal.addEventListener && signal.addEventListener('abort', onabort));
+
+  const {signal} = controller;
+
+  signal.unsubscribe = unsubscribe;
+
+  return [signal, () => {
+    timer && clearTimeout(timer);
+    timer = null;
+  }];
+}
+
+export default composeSignals;