feat: allow for AbortController to be optional (#211)

Author: Tymek

src/index.test.ts

@@ -642,6 +642,27 @@ test('Should not trigger error on abort', async () => {
     await client.updateContext({ userId: '789' });
 });
 
+test('Should run without abort controller', async () => {
+    fetchMock.mockResponse(JSON.stringify(data));
+    const abortSpy = jest.spyOn(AbortController.prototype, 'abort');
+
+    const config: IConfig = {
+        url: 'http://localhost/test',
+        clientKey: '12',
+        appName: 'web',
+        createAbortController: () => null,
+    };
+    const client = new UnleashClient(config);
+
+    await client.start();
+    client.updateContext({ userId: '123' });
+    client.updateContext({ userId: '456' });
+    await client.updateContext({ userId: '789' });
+
+    expect(abortSpy).toBeCalledTimes(0);
+    abortSpy.mockRestore();
+});
+
 test.each([400, 401, 403, 404, 429, 500, 502, 503])(
     'Should publish error when fetch receives a %d error',
     async (errorCode) => {

src/index.ts

@@ -46,7 +46,7 @@ interface IConfig extends IStaticContext {
     storageProvider?: IStorageProvider;
     context?: IMutableContext;
     fetch?: any;
-    createAbortController?: () => AbortController;
+    createAbortController?: () => AbortController | null;
     bootstrap?: IToggle[];
     bootstrapOverride?: boolean;
     headerName?: string;
@@ -100,7 +100,9 @@ export const resolveFetch = () => {
     try {
         if (typeof window !== 'undefined' && 'fetch' in window) {
             return fetch.bind(window);
-        } else if ('fetch' in globalThis) {
+        }
+
+        if ('fetch' in globalThis) {
             return fetch.bind(globalThis);
         }
     } catch (e) {
@@ -114,7 +116,9 @@ const resolveAbortController = () => {
     try {
         if (typeof window !== 'undefined' && 'AbortController' in window) {
             return () => new window.AbortController();
-        } else if ('fetch' in globalThis) {
+        }
+
+        if ('fetch' in globalThis) {
             return () => new globalThis.AbortController();
         }
     } catch (e) {
@@ -135,7 +139,7 @@ export class UnleashClient extends TinyEmitter {
     private metrics: Metrics;
     private ready: Promise<void>;
     private fetch: any;
-    private createAbortController?: () => AbortController;
+    private createAbortController?: () => AbortController | null;
     private abortController?: AbortController | null;
     private bootstrap?: IToggle[];
     private bootstrapOverride: boolean;
@@ -431,8 +435,7 @@ export class UnleashClient extends TinyEmitter {
             if (this.abortController) {
                 this.abortController.abort();
             }
-            this.abortController =
-                this.createAbortController && this.createAbortController();
+            this.abortController = this.createAbortController?.();
             const signal = this.abortController
                 ? this.abortController.signal
                 : undefined;