fix(http): remove axios config mutation

Author: soyuka

packages/common/http/http.service.ts

@@ -73,11 +73,7 @@ export class HttpService {
     ...args: any[]
   ) {
     return new Observable<AxiosResponse<T>>(subscriber => {
-      let config: AxiosRequestConfig = args[args.length - 1];
-      if (!config) {
-        config = {};
-        args[args.length - 1] = config;
-      }
+      const config = args[args.length - 1] ? { ...args[args.length - 1] } : {};
 
       let cancelSource: CancelTokenSource;
       if (!config.cancelToken) {

packages/common/test/http/http.service.spec.ts

@@ -0,0 +1,17 @@
+import { expect } from 'chai';
+import { HttpService } from '../../http/http.service';
+import { AxiosRequestConfig, AxiosInstance } from 'axios';
+
+describe('HttpService', () => {
+  it('should not mutate user-given axios options object', () => {
+    const http = new HttpService({ get: () => Promise.resolve() } as any);
+    const options: AxiosRequestConfig = {};
+
+    http
+      .get('/', options)
+      .toPromise()
+      .then(() => {
+        expect(options.cancelToken).to.be.undefined;
+      });
+  });
+});