diff --git a/.github/workflows/core.yml b/.github/workflows/core.yml
index 028990b..841cbca 100644
--- a/.github/workflows/core.yml
+++ b/.github/workflows/core.yml
@@ -48,7 +48,6 @@ jobs:
           - ubuntu-latest
         node:
           - 14.x
-          - 12.x
     steps:
       - name: Checkout
         uses: actions/checkout@v2
diff --git a/.nycrc.yml b/.nycrc.yml
index 5ffcf51..459cdee 100644
--- a/.nycrc.yml
+++ b/.nycrc.yml
@@ -10,7 +10,9 @@ require:
   - source-map-support/register
 exclude:
   - '**/*.spec.ts'
+  - node_modules/**/*
   - build/**/*
+  - 'projects/**/test-util/**/*'
   - test/**/*
 sourceMap: true
 instrument: true
diff --git a/package.json b/package.json
index 3af4b3a..518700f 100644
--- a/package.json
+++ b/package.json
@@ -34,6 +34,7 @@
   "devDependencies": {
     "@alorel-personal/conventional-changelog-alorel": "^2.1.3",
     "@alorel/commons-array-types": "^1.1.0",
+    "@alorel/commons-obj": "^1.0.2",
     "@alorel/eslint-config-base": "^1.0.17",
     "@alorel/eslint-config-typescript": "^1.0.17",
     "@alorel/rollup-plugin-copy": "^1.0.2",
@@ -48,12 +49,14 @@
     "@semantic-release/github": "^7.1.1",
     "@semantic-release/npm": "^7.0.6",
     "@types/chai": "^4.2.12",
+    "@types/chai-as-promised": "^7.1.3",
     "@types/jsdom": "^16.2.4",
     "@types/mocha": "^8.0.3",
     "@types/node": "^14.11.2",
     "@typescript-eslint/eslint-plugin": "^4.2.0",
     "@typescript-eslint/parser": "^4.2.0",
     "chai": "^4.2.0",
+    "chai-as-promised": "^7.1.1",
     "cross-env": "^7.0.2",
     "del-cli": "^3.0.1",
     "doctoc": "^1.4.0",
diff --git a/projects/core/index.spec.ts b/projects/core/index.spec.ts
deleted file mode 100644
index 785ae72..0000000
--- a/projects/core/index.spec.ts
+++ /dev/null
@@ -1,38 +0,0 @@
-import {JSDOM} from 'jsdom';
-import type {Mockttp} from 'mockttp';
-import {getLocal} from 'mockttp';
-import {rxAjax} from './lib/rxAjax';
-import type {RxAjax} from './types/RxAjax';
-
-describe('tmp', () => {
-  let baseAjax: RxAjax;
-  let server: Mockttp = null as any;
-  before(() => {
-    const {window: {XMLHttpRequest}} = new JSDOM('').window;
-    baseAjax = rxAjax({
-      createXHR: () => {
-        const req = new XMLHttpRequest();
-        req.withCredentials = false;
-
-        return req;
-      }
-    });
-    server = getLocal();
-
-    return server.start();
-  });
-
-  after(() => server?.stop());
-
-  it('Summin', async () => {
-    await server.get('/potat')
-      // eslint-disable-next-line @typescript-eslint/no-magic-numbers
-      .thenReply(200, JSON.stringify({potato: 'salad'}), {'access-control-allow-origin': '*'});
-    const url = server.urlFor('/potat');
-    console.log('potat url', url);
-
-    const rsp = await baseAjax.getJSON(url).toPromise();
-
-    console.log({rsp});
-  });
-});
diff --git a/projects/core/lib/makeRequest.spec.ts b/projects/core/lib/makeRequest.spec.ts
new file mode 100644
index 0000000..a2ff92f
--- /dev/null
+++ b/projects/core/lib/makeRequest.spec.ts
@@ -0,0 +1,61 @@
+import {expect} from 'chai';
+import type {Mockttp} from 'mockttp';
+import {RSP_HEADERS, setUpMockServer} from '../test-util/MockServer';
+import {testAjaxOpts} from '../test-util/testAjax';
+import type {UnprocessedResponse} from '../types/Response';
+import {makeRequest} from './makeRequest';
+
+/* eslint-disable @typescript-eslint/no-magic-numbers */
+
+describe('makeRequest', function () {
+
+  describe('Successful response', () => {
+    let server: Mockttp;
+    let url: string;
+    let rsp: UnprocessedResponse<any>;
+
+    setUpMockServer(true, v => (server = v));
+    before(async () => {
+      await server.get('/success').thenJson(200, {su: 'ccess'}, RSP_HEADERS);
+      url = server.urlFor('/success');
+      rsp = await makeRequest<any>({...testAjaxOpts, preAsync: [], url}).toPromise();
+    });
+
+    it('Ok should be true', () => {
+      expect(rsp.ok).to.eq(true);
+    });
+
+    it('Original request should contain custom props', () => {
+      expect(rsp.response.request).to.haveOwnProperty('preAsync');
+    });
+
+    it('Should have json response', () => {
+      expect(rsp.response.response).to.deep.eq({su: 'ccess'});
+    });
+  });
+
+  describe('Error response', () => {
+    let server: Mockttp;
+    let url: string;
+    let rsp: UnprocessedResponse<any>;
+
+    setUpMockServer(true, v => (server = v));
+    before(async () => {
+      await server.get('/fail').thenJson(420, {fai: 'lure'}, RSP_HEADERS);
+      url = server.urlFor('/fail');
+      rsp = await makeRequest<any>({...testAjaxOpts, postAsync: [], url}).toPromise();
+    });
+
+    it('Ok should be true', () => {
+      expect(rsp.ok).to.eq(false);
+    });
+
+    it('Original request should contain custom props', () => {
+      expect(rsp.response.request).to.haveOwnProperty('postAsync');
+    });
+
+    it('Should have json response', () => {
+      expect(rsp.response.response).to.deep.eq({fai: 'lure'});
+    });
+  });
+});
diff --git a/projects/core/lib/merge.spec.ts b/projects/core/lib/merge.spec.ts
new file mode 100644
index 0000000..c42b83e
--- /dev/null
+++ b/projects/core/lib/merge.spec.ts
@@ -0,0 +1,55 @@
+import {expect} from 'chai';
+import {identity, noop, of} from 'rxjs';
+import type {RxAjaxOptions as Opt} from '../types/Options';
+import {merge} from './merge';
+
+/* eslint-disable @typescript-eslint/no-magic-numbers */
+
+describe('merge', function () {
+  describe('headers', () => {
+    it('Should omit if absent in both defaults and custom', () => {
+      const d: Opt = {url: '/foo'};
+      const c: Opt = {withCredentials: true};
+      expect(merge(d, c)).to.deep.eq({url: '/foo', withCredentials: true});
+    });
+
+    it('Should merge if it has custom headers', () => {
+      const d: Opt = {headers: {foo: 'bar'}};
+      const c: Opt = {headers: {qux: 'baz'}};
+      expect(merge(d, c)).to.deep.eq({headers: {foo: 'bar', qux: 'baz'}});
+    });
+
+    it('Shouldn\'t change reference of using defaults', () => {
+      const d: Opt = {headers: {}};
+      const c: Opt = {url: '/'};
+      expect(merge(d, c).headers).to.eq(d.headers);
+    });
+  });
+
+  describe('arrays', () => {
+    it('Should omit if absent on both', () => {
+      expect(merge({}, {})).to.deep.eq({});
+    });
+
+    it('Should reuse default instance', () => {
+      const d: Opt = {pre: [identity]};
+      expect(merge(d, {}).pre).to.eq(d.pre);
+    });
+
+    it('Should reuse custom instance', () => {
+      const d: Opt = {post: [identity as any]};
+      expect(merge({}, d).post).to.eq(d.post);
+    });
+
+    it('Should concat and dedupe', () => {
+      const d: Opt = {postAsync: [identity, noop] as any[]};
+      const c: Opt = {postAsync: [noop, of] as any[]};
+      const {postAsync} = merge(d, c);
+
+      expect(postAsync).to.have.lengthOf(3, 'length');
+      expect(postAsync![0]).to.eq(identity, '[identity]');
+      expect(postAsync![1]).to.eq(noop, '[noop]');
+      expect(postAsync![2]).to.eq(of, '[of]');
+    });
+  });
+});
diff --git a/projects/core/lib/merge.ts b/projects/core/lib/merge.ts
index fdfca30..a4a8650 100644
--- a/projects/core/lib/merge.ts
+++ b/projects/core/lib/merge.ts
@@ -37,8 +37,11 @@ export function merge(defaults: RxAjaxOptions, custom: RxAjaxOptions): RxAjaxOpt
   } = custom;
 
   const out: RxAjaxOptions = {...defaults, ...restCustom};
-  if (defaults.headers || headersCustom) {
-    out.headers = {...defaults.headers, ...headersCustom};
+  if (headersCustom) {
+    out.headers = {
+      ...out.headers,
+      ...headersCustom
+    };
   }
   mergeProp(out, 'pre', defaults.pre, preCustom);
   mergeProp(out, 'preAsync', defaults.preAsync, preCustomAsync);
diff --git a/projects/core/lib/middleware/applyAsyncPreMiddleware.ts b/projects/core/lib/middleware/applyAsyncPreMiddleware.ts
index 90220c4..0dd1fb7 100644
--- a/projects/core/lib/middleware/applyAsyncPreMiddleware.ts
+++ b/projects/core/lib/middleware/applyAsyncPreMiddleware.ts
@@ -1,6 +1,6 @@
 import type {MonoTypeOperatorFunction as MonoOp, Observable} from 'rxjs';
 import {of} from 'rxjs';
-import {last, switchMap} from 'rxjs/operators';
+import {switchMap} from 'rxjs/operators';
 import type {RxAjaxOptions, RxAjaxPostAsyncHook} from '../../types/Options';
 
 /** @internal */
@@ -12,8 +12,7 @@ export function applyAsyncPreMiddleware(opts: RxAjaxOptions): null | Observable<
 
   const src$ = of(opts);
   const args: Array<MonoOp<any>> = (preAsync as RxAjaxPostAsyncHook[])
-    .map(switchMap)
-    .concat(last());
+    .map(switchMap);
 
   return src$.pipe.apply(src$, args); // eslint-disable-line prefer-spread
 }
diff --git a/projects/core/lib/middleware/applyPostAsyncMiddleware.ts b/projects/core/lib/middleware/applyPostAsyncMiddleware.ts
index 953d8d3..91cd869 100644
--- a/projects/core/lib/middleware/applyPostAsyncMiddleware.ts
+++ b/projects/core/lib/middleware/applyPostAsyncMiddleware.ts
@@ -1,28 +1,16 @@
-import type {MonoTypeOperatorFunction as MonoOp, Observable} from 'rxjs';
-import {from, of} from 'rxjs';
-import {last, switchMap} from 'rxjs/operators';
+import type {MonoTypeOperatorFunction as MonoOp} from 'rxjs';
+import {pipe} from 'rxjs';
+import {switchMap} from 'rxjs/operators';
 import type {RxAjaxOptions} from '../../types/Options';
+import type {RxAjaxPostAsyncHook} from '../../types/Options';
 import type {UnprocessedResponse} from '../../types/Response';
 
 /** @internal */
 export function applyPostAsyncMiddleware(
-  idx: number,
   middleware: Required<RxAjaxOptions>['postAsync']
 ): MonoOp<UnprocessedResponse<any>> {
-  return switchMap(
-    function applyPostMiddlewareExecutor(response: UnprocessedResponse<any>): Observable<UnprocessedResponse<any>> {
-      if (response.stop) {
-        return of(response);
-      }
+  const pipes = (middleware as RxAjaxPostAsyncHook[])
+    .map((mid): MonoOp<UnprocessedResponse<any>> => switchMap(mid));
 
-      const pipes: Array<MonoOp<any>> = [last()];
-      if (middleware[idx + 1]) {
-        pipes[1] = applyPostAsyncMiddleware(idx + 1, middleware);
-      }
-
-      const src$ = from(middleware[idx](response));
-
-      return src$.pipe.apply(src$, pipes) as Observable<UnprocessedResponse<any>>; // eslint-disable-line prefer-spread
-    }
-  );
+  return pipe.apply(null, pipes as any[]) as MonoOp<UnprocessedResponse<any>>; // eslint-disable-line prefer-spread
 }
diff --git a/projects/core/lib/middleware/applyPostMiddleware.ts b/projects/core/lib/middleware/applyPostMiddleware.ts
index 90fede2..f9a10bd 100644
--- a/projects/core/lib/middleware/applyPostMiddleware.ts
+++ b/projects/core/lib/middleware/applyPostMiddleware.ts
@@ -9,16 +9,9 @@ export function applyPostMiddleware<T>(
 ): MonoTypeOperatorFunction<UnprocessedResponse<T>> {
   return map(
     function applyPostMiddlewareExecutor(rsp: UnprocessedResponse<T>): UnprocessedResponse<T> {
-      if (rsp.stop) {
-        return rsp;
-      }
-
       let out = rsp;
       for (let i = 0; i < middleware.length; i++) {
         out = middleware[i](out);
-        if (out.stop) {
-          break;
-        }
       }
 
       return out;
diff --git a/projects/core/lib/rxAjax.spec.ts b/projects/core/lib/rxAjax.spec.ts
new file mode 100644
index 0000000..48a35bb
--- /dev/null
+++ b/projects/core/lib/rxAjax.spec.ts
@@ -0,0 +1,133 @@
+import type {Obj} from '@alorel/commons-obj';
+import * as chai from 'chai';
+import * as promiseChai from 'chai-as-promised';
+import type {Mockttp} from 'mockttp';
+import type {Observable} from 'rxjs';
+import {of} from 'rxjs';
+import {RSP_HEADERS, setUpMockServer, setUpRequestDebugger} from '../test-util/MockServer';
+import {testAjax} from '../test-util/testAjax';
+import type {RxAjaxOptions} from '../types/Options';
+import type {RxAjaxResponse, UnprocessedResponse} from '../types/Response';
+import type {RxAjax} from '../types/RxAjax';
+
+/* eslint-disable @typescript-eslint/no-magic-numbers */
+
+describe('rxAjax', function () {
+  const expect = chai.use(promiseChai).expect;
+
+  describe('middleware', () => {
+    let server: Mockttp;
+    setUpMockServer(true, v => (server = v));
+    before(setUpRequestDebugger(() => server));
+
+    it('Should apply middleware', async () => {
+      const url = server.urlFor('/test-middleware');
+      const ob$ = testAjax.getJSON(url, {
+        post: [
+          (rsp): UnprocessedResponse<any> => ({
+            ...rsp,
+            response: {
+              ...rsp.response,
+              customProp: 'is-set'
+            } as unknown as any
+          })
+        ],
+        postAsync: [
+          (rsp: UnprocessedResponse<any>) => of<UnprocessedResponse<any>>({
+            ...rsp,
+            ok: true,
+            response: {
+              ...rsp.response,
+              status: 420
+            } as unknown as RxAjaxResponse
+          })
+        ],
+        pre: [
+          (req): RxAjaxOptions => ({
+            ...req,
+            headers: {
+              ...req.body,
+              'content-type': 'potatoes'
+            }
+          })
+        ],
+        preAsync: [
+          (req): Observable<RxAjaxOptions> => of({
+            ...req,
+            method: 'DELETE'
+          })
+        ]
+      });
+
+      const rsp$ = (await ob$.toPromise()) as RxAjaxResponse & Obj;
+      const {response: {method, headers}, status, customProp} = rsp$;
+
+
+      expect(status).to.eq(420, 'Status');
+      expect(method).to.eq('DELETE', 'method');
+      expect(headers['content-type']).to.eq('potatoes', 'sent headers');
+      expect(customProp).to.eq('is-set', 'customProp');
+
+      return {headers, method, status};
+    });
+  });
+
+  describe('request methods', () => {
+    let server: Mockttp;
+    setUpMockServer(true, v => (server = v));
+    before(setUpRequestDebugger(() => server));
+
+    const bodyMethods: Array<keyof RxAjax> = ['patch', 'post', 'put'];
+    const nonBodymethods: Array<keyof RxAjax> = ['get', 'delete'];
+
+    for (const meth of bodyMethods) {
+      it(`Should make ${meth.toUpperCase()} requests`, async () => {
+        const url = server.urlFor(`/meth-${meth}`);
+        const body = {[Math.random().toString()]: Math.random()};
+        const p$: Promise<RxAjaxResponse> = testAjax[meth as 'post'].call(null, url, body).toPromise();
+        const {response: rsp} = await p$;
+
+        expect(rsp.method).to.eq(meth.toUpperCase(), 'Method');
+        expect(rsp.path).to.eq(`/meth-${meth}`, 'Path');
+        expect(rsp.body.json).to.deep.eq(body);
+      });
+    }
+
+    for (const meth of nonBodymethods) {
+      it(`Should make ${meth.toUpperCase()} requests`, async () => {
+        const url = server.urlFor(`/meth-${meth}`);
+        const p$: Promise<RxAjaxResponse> = testAjax[meth as 'get'].call(null, url).toPromise();
+        const {response: rsp} = await p$;
+
+        expect(rsp.method).to.eq(meth.toUpperCase(), 'Method');
+        expect(rsp.path).to.eq(`/meth-${meth}`, 'Path');
+      });
+    }
+  });
+
+  describe('extend', () => {
+    let server: Mockttp;
+    setUpMockServer(true, v => (server = v));
+
+    it('Should extend settings', async () => {
+      const b = testAjax.extend({method: 'delete', url: '/delete'});
+
+      await server.anyRequest()
+        .thenCallback(req => {
+          if (req.path === '/delete' && ['OPTIONS', 'DELETE'].includes(req.method)) {
+            return {
+              headers: RSP_HEADERS,
+              status: 200
+            };
+          }
+
+          return {status: 404};
+        });
+
+      await b(server.urlFor('/delete')).toPromise();
+
+      expect(1).to.eq(1);
+    });
+  });
+
+});
diff --git a/projects/core/lib/rxAjax.ts b/projects/core/lib/rxAjax.ts
index c963842..d31b1e3 100644
--- a/projects/core/lib/rxAjax.ts
+++ b/projects/core/lib/rxAjax.ts
@@ -2,7 +2,7 @@ import type {Observable} from 'rxjs';
 import {of, throwError} from 'rxjs';
 import {AjaxError} from 'rxjs/ajax';
 import {switchMap} from 'rxjs/operators';
-import type {RxAjaxOptions, RxAjaxRequestOptions} from '../types/Options';
+import type {RxAjaxOptions} from '../types/Options';
 import type {RxAjaxResponse, UnprocessedResponse} from '../types/Response';
 import type {RxAjax} from '../types/RxAjax';
 import {makeRequest} from './makeRequest';
@@ -37,14 +37,14 @@ function innerExecutor<T>(mergedOpts: RxAjaxOptions): Observable<RxAjaxResponse<
   }
 
   if (opts.postAsync?.length) {
-    req$ = req$.pipe(applyPostAsyncMiddleware(0, opts.postAsync));
+    req$ = req$.pipe(applyPostAsyncMiddleware(opts.postAsync));
   }
 
   return req$.pipe(switchMap(unwrapResponse));
 }
 
 function makeBodyMethod(
-  method: keyof RxAjax,
+  method: string,
   executor: (req: RxAjaxOptions) => Observable<RxAjaxResponse>
 ): RxAjax['post'] {
   return function rxAjaxBodyMethodExecutor(url, body, opts) {
@@ -61,31 +61,27 @@ export function rxAjax<BaseT = any>(defaults: RxAjaxOptions = {}): RxAjax<BaseT>
     return innerExecutor(merge(defaults, mergeableOptions));
   }
 
-  rxAjaxExecutor.extend = function extend<T = any>(opts: RxAjaxRequestOptions): RxAjax<T> {
-    return rxAjax<T>(merge(defaults, opts));
-  };
-
   const ext: Pick<RxAjax<BaseT>, Props> = {
     delete(url, opts) {
-      return rxAjaxExecutor({...opts, method: 'delete', url});
+      return rxAjaxExecutor({...opts, method: 'DELETE', url});
     },
     extend(opts) {
       return rxAjax(merge(defaults, opts));
     },
     get(url, opts) {
-      return rxAjaxExecutor({...opts, method: 'get', url});
+      return rxAjaxExecutor({...opts, method: 'GET', url});
     },
     getJSON(url, opts) {
       return rxAjaxExecutor({
         ...opts,
-        method: 'get',
+        method: 'GET',
         responseType: 'json',
         url
       });
     },
-    patch: makeBodyMethod('patch', rxAjaxExecutor),
-    post: makeBodyMethod('post', rxAjaxExecutor),
-    put: makeBodyMethod('put', rxAjaxExecutor)
+    patch: makeBodyMethod('PATCH', rxAjaxExecutor),
+    post: makeBodyMethod('POST', rxAjaxExecutor),
+    put: makeBodyMethod('PUT', rxAjaxExecutor)
   };
 
   return Object.assign(rxAjaxExecutor, ext);
diff --git a/projects/core/package.json b/projects/core/package.json
index 472044c..e70cf2e 100644
--- a/projects/core/package.json
+++ b/projects/core/package.json
@@ -4,6 +4,7 @@
   "description": "Utility wrapper for rxjs' ajax function",
   "dependencies": {
     "@alorel/commons-array-types": "^1.0.0",
+    "@alorel/commons-obj": "^1.0.2",
     "tslib": "^2.0.0 || ^1.11.0"
   },
   "peerDependencies": {
@@ -27,4 +28,4 @@
     "access": "public",
     "registry": "https://npm.pkg.github.com"
   }
-}
\ No newline at end of file
+}
diff --git a/projects/core/test-util/MockServer.ts b/projects/core/test-util/MockServer.ts
new file mode 100644
index 0000000..2c7f2ca
--- /dev/null
+++ b/projects/core/test-util/MockServer.ts
@@ -0,0 +1,39 @@
+import type {MockedEndpoint, Mockttp} from 'mockttp';
+import {getLocal} from 'mockttp';
+
+export const RSP_HEADERS = {'access-control-allow-origin': '*'};
+
+export function setUpMockServer(once: boolean, setter: (v: Mockttp) => void): void {
+  let server: Mockttp = null as any;
+  const bf = async () => {
+    server = getLocal();
+    await server.start();
+    setter(server);
+  };
+  const af = () => {
+    const stop$ = server?.stop();
+    setter(server = null as any);
+
+    return stop$;
+  };
+
+  if (once) {
+    before(bf);
+    after(af);
+  } else {
+    beforeEach(bf);
+    afterEach(af);
+  }
+}
+
+export function setUpRequestDebugger(getServer: () => Mockttp): () => Promise<MockedEndpoint> {
+  return () => getServer().anyRequest()
+    .thenCallback(({method, path, headers, body}) => ({
+      body: JSON.stringify({body, headers, method, path}),
+      headers: {
+        ...RSP_HEADERS,
+        'content-type': 'application/json'
+      },
+      status: 200
+    }));
+}
diff --git a/projects/core/test-util/testAjax.ts b/projects/core/test-util/testAjax.ts
new file mode 100644
index 0000000..848aa8e
--- /dev/null
+++ b/projects/core/test-util/testAjax.ts
@@ -0,0 +1,11 @@
+import {JSDOM} from 'jsdom';
+import {rxAjax} from '../lib/rxAjax';
+import type {RxAjaxOptions} from '../types/Options';
+
+const {window: {XMLHttpRequest}} = new JSDOM('');
+
+export const testAjaxOpts: RxAjaxOptions = {
+  createXHR: () => new XMLHttpRequest(),
+  headers: {'content-type': 'application/json'}
+};
+export const testAjax = rxAjax(testAjaxOpts);
diff --git a/projects/core/types/Options.ts b/projects/core/types/Options.ts
index f9f9480..8fcc86e 100644
--- a/projects/core/types/Options.ts
+++ b/projects/core/types/Options.ts
@@ -1,4 +1,5 @@
 import type {Arrayish} from '@alorel/commons-array-types';
+import type {Obj} from '@alorel/commons-obj';
 import type {ObservableInput} from 'rxjs';
 import type {AjaxRequest} from 'rxjs/ajax';
 import type {UnprocessedResponse} from './Response';
@@ -6,7 +7,9 @@ import type {UnprocessedResponse} from './Response';
 export type RxAjaxPostAsyncHook = <I = any, O extends I = any>(request: UnprocessedResponse<I>)
   => ObservableInput<UnprocessedResponse<O>>;
 
-export interface RxAjaxOptions extends AjaxRequest {
+export interface RxAjaxOptions extends Omit<AjaxRequest, 'headers'> {
+  headers?: Obj<string>;
+
   post?: Arrayish<(<I = any, O extends I = any>(request: UnprocessedResponse<I>) => UnprocessedResponse<O>)>;
 
   postAsync?: Arrayish<RxAjaxPostAsyncHook>;
diff --git a/projects/core/types/Response.ts b/projects/core/types/Response.ts
index 817942c..916144c 100644
--- a/projects/core/types/Response.ts
+++ b/projects/core/types/Response.ts
@@ -2,20 +2,14 @@ import type {AjaxResponse} from 'rxjs/ajax';
 import type {RxAjaxErrorResponse} from './Error';
 import type {RxAjaxOptions} from './Options';
 
-interface BaseUnprocessedResponse {
-  ok: boolean;
-
-  stop?: true;
-}
-
-export interface UnprocessedSuccessResponse<T> extends BaseUnprocessedResponse{
+export interface UnprocessedSuccessResponse<T> {
 
   ok: true;
 
   response: RxAjaxResponse<T>;
 }
 
-export interface UnprocessedErrorResponse extends BaseUnprocessedResponse{
+export interface UnprocessedErrorResponse {
   ok: false;
 
   response: RxAjaxErrorResponse;
diff --git a/projects/core/types/RxAjax.ts b/projects/core/types/RxAjax.ts
index 82fa135..0674ab3 100644
--- a/projects/core/types/RxAjax.ts
+++ b/projects/core/types/RxAjax.ts
@@ -5,7 +5,7 @@ import type {RxAjaxResponse} from './Response';
 export interface RxAjax<BaseT = any> {
   delete<T = BaseT>(url: string, opts?: RxAjaxRequestOptions): Observable<RxAjaxResponse<T>>;
 
-  extend<T = any>(opts: RxAjaxRequestOptions): RxAjax<T>;
+  extend<T = any>(opts: RxAjaxOptions): RxAjax<T>;
 
   get<T = BaseT>(url: string, opts?: RxAjaxRequestOptions): Observable<RxAjaxResponse<T>>;
 
diff --git a/yarn.lock b/yarn.lock
index cd420b2..303ebd3 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -22,6 +22,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@alorel/commons-obj@npm:^1.0.2":
+  version: 1.0.2
+  resolution: "@alorel/commons-obj@npm:1.0.2::__archiveUrl=https%3A%2F%2Fnpm.pkg.github.com%2Fdownload%2F%40alorel%2Fcommons-obj%2F1.0.2%2F7b504d0ff6580347d8ed4a4ce22b72e464f1fd11802bed4689a36785d16022b2"
+  checksum: 2/bb71acb3a3d7afa972952bb18ea7a713cdc58eca2c1bbfabd304014bdec98647370b5a326a563f3576f2c5d40be9eb5b4a87e03dd93e157e2114e9d2f32776b3
+  languageName: node
+  linkType: hard
+
 "@alorel/eslint-config-base@npm:^1.0.17":
   version: 1.0.17
   resolution: "@alorel/eslint-config-base@npm:1.0.17::__archiveUrl=https%3A%2F%2Fnpm.pkg.github.com%2Fdownload%2F%40alorel%2Feslint-config-base%2F1.0.17%2F0cd00f7cc51881f31cf552fb4944779e1bd38426816ee479bae829e9e9491d11"
@@ -111,6 +118,7 @@ __metadata:
   dependencies:
     "@alorel-personal/conventional-changelog-alorel": ^2.1.3
     "@alorel/commons-array-types": ^1.1.0
+    "@alorel/commons-obj": ^1.0.2
     "@alorel/eslint-config-base": ^1.0.17
     "@alorel/eslint-config-typescript": ^1.0.17
     "@alorel/rollup-plugin-copy": ^1.0.2
@@ -125,12 +133,14 @@ __metadata:
     "@semantic-release/github": ^7.1.1
     "@semantic-release/npm": ^7.0.6
     "@types/chai": ^4.2.12
+    "@types/chai-as-promised": ^7.1.3
     "@types/jsdom": ^16.2.4
     "@types/mocha": ^8.0.3
     "@types/node": ^14.11.2
     "@typescript-eslint/eslint-plugin": ^4.2.0
     "@typescript-eslint/parser": ^4.2.0
     chai: ^4.2.0
+    chai-as-promised: ^7.1.1
     cross-env: ^7.0.2
     del-cli: ^3.0.1
     doctoc: ^1.4.0
@@ -911,7 +921,16 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/chai@npm:^4.2.12":
+"@types/chai-as-promised@npm:^7.1.3":
+  version: 7.1.3
+  resolution: "@types/chai-as-promised@npm:7.1.3"
+  dependencies:
+    "@types/chai": "*"
+  checksum: 2/71f383b20c556bf227b4e117f721fb7d92dcdaeefe7c352b301d59e0eca9dc2c72538c0f2829da62ba06b2c26002a730c5b7137b43aaac76f7c9ff8fdc9847f2
+  languageName: node
+  linkType: hard
+
+"@types/chai@npm:*, @types/chai@npm:^4.2.12":
   version: 4.2.12
   resolution: "@types/chai@npm:4.2.12"
   checksum: 2/5dc6d541d748dbf95e0f0b1a39177e0bd8b37f143307cce6a93baf3d6cb44fead65fddb582ce9397aa14b1a76117e5d398fa322f92182074b7d53e5d2f669a19
@@ -2044,6 +2063,17 @@ __metadata:
   languageName: node
   linkType: hard
 
+"chai-as-promised@npm:^7.1.1":
+  version: 7.1.1
+  resolution: "chai-as-promised@npm:7.1.1"
+  dependencies:
+    check-error: ^1.0.2
+  peerDependencies:
+    chai: ">= 2.1.2 < 5"
+  checksum: 2/747b85b679f8decdbb83f249883519ea5d4de055f2502fb830db28175af1e4f02a6a8c505d6edce1f2cf28c5512d5e3666db92906b80e77fca30b37c3e5cd360
+  languageName: node
+  linkType: hard
+
 "chai@npm:^4.2.0":
   version: 4.2.0
   resolution: "chai@npm:4.2.0"