fix(fetch): optimize signals composing logic; (#6582)

test/unit/helpers/composeSignals.js

@@ -0,0 +1,43 @@
+import assert from 'assert';
+import composeSignals from '../../../lib/helpers/composeSignals.js';
+
+describe('helpers::composeSignals', () => {
+  before(function () {
+    if (typeof AbortController !== 'function') {
+      this.skip();
+    }
+  });
+
+  it('should abort when any of the signals abort', () => {
+    let called;
+
+    const controllerA = new AbortController();
+    const controllerB = new AbortController();
+
+    const signal = composeSignals([controllerA.signal, controllerB.signal]);
+
+    signal.addEventListener('abort', () => {
+      called = true;
+    });
+
+    controllerA.abort(new Error('test'));
+
+    assert.ok(called);
+  });
+
+  it('should abort on timeout', async () => {
+    const signal = composeSignals([], 100);
+
+    await new Promise(resolve => {
+      signal.addEventListener('abort', resolve);
+    });
+
+    assert.match(String(signal.reason), /timeout 100 of ms exceeded/);
+  });
+
+  it('should return undefined if signals and timeout are not provided', async () => {
+    const signal = composeSignals([]);
+
+    assert.strictEqual(signal, undefined);
+  });
+});