defaultHeaders enhance

- `defaultHeaders`: new strategy options - `defaults-set`, `defaults-append` (minor)
- `defaultHeaders`: default strategy now is `set` (major)
- some deps updated (patch)

deno.json

@@ -8,8 +8,8 @@
   },
   "imports": {
     "@deno/dnt": "jsr:@deno/dnt@^0.41.3",
-    "@std/expect": "jsr:@std/expect@^1.0.6",
-    "@std/testing": "jsr:@std/testing@^1.0.3",
+    "@std/expect": "jsr:@std/expect@^1.0.9",
+    "@std/testing": "jsr:@std/testing@^1.0.6",
     "#fetch": "./src/fetch/mod.ts",
     "#response": "./src/response/mod.ts"
   },

src/fetch/__test__/applyMiddleware.test.ts

@@ -1,9 +1,9 @@
-import { it } from '@std/testing/bdd';
+import { test } from '@std/testing/bdd';
 import { expect } from '@std/expect';
 import { applyMiddleware } from '../apply-middleware.ts';
 import type { Middleware } from '../types.ts';
 
-it('should apply middleware in the order in which they are passed', async () => {
+test('should apply middleware in the order in which they are passed', async () => {
   const log: string[] = [];
 
   const foo: Middleware = async (request, next) => {

src/middleware/__test__/default-headers.test.ts

@@ -0,0 +1,119 @@
+import { test } from '@std/testing/bdd';
+import { expect } from '@std/expect';
+import { defaultHeaders } from '../default-headers.ts';
+
+test('strategy "set", should be default', async () => {
+  const middleware = defaultHeaders({
+    'content-type': 'application/json',
+  });
+
+  const request = new Request('https://foo.bar', {
+    method: 'POST',
+    body: JSON.stringify({ foo: 'bar' }),
+  });
+
+  expect(request.headers.get('Content-Type')).toBe('text/plain;charset=UTF-8');
+
+  const next = (req: Request) => {
+    state.request = req;
+    return new Response('ok');
+  };
+
+  const state: { request: Request | null } = {
+    request: null,
+  };
+
+  await middleware(request, next);
+
+  expect(state.request?.headers.get('Content-Type')).toBe('application/json');
+});
+
+test('strategy "append"', async () => {
+  const middleware = defaultHeaders({
+    'content-type': 'application/json',
+  }, {
+    strategy: 'append',
+  });
+
+  const request = new Request('https://foo.bar', {
+    method: 'POST',
+    body: JSON.stringify({ foo: 'bar' }),
+  });
+
+  expect(request.headers.get('Content-Type')).toBe('text/plain;charset=UTF-8');
+
+  const next = (req: Request) => {
+    state.request = req;
+    return new Response('ok');
+  };
+
+  const state: { request: Request | null } = {
+    request: null,
+  };
+
+  await middleware(request, next);
+
+  expect(state.request?.headers.get('Content-Type')).toBe(
+    'text/plain;charset=UTF-8, application/json',
+  );
+});
+
+test('strategy "defaults-set"', async () => {
+  const middleware = defaultHeaders({
+    'content-type': 'application/json',
+  }, {
+    strategy: 'defaults-set',
+  });
+
+  const request = new Request('https://foo.bar', {
+    method: 'POST',
+    body: JSON.stringify({ foo: 'bar' }),
+  });
+
+  expect(request.headers.get('Content-Type')).toBe('text/plain;charset=UTF-8');
+
+  const next = (req: Request) => {
+    state.request = req;
+    return new Response('ok');
+  };
+
+  const state: { request: Request | null } = {
+    request: null,
+  };
+
+  await middleware(request, next);
+
+  expect(state.request?.headers.get('Content-Type')).toBe(
+    'text/plain;charset=UTF-8',
+  );
+});
+
+test('strategy "defaults-set"', async () => {
+  const middleware = defaultHeaders({
+    'content-type': 'application/json',
+  }, {
+    strategy: 'defaults-append',
+  });
+
+  const request = new Request('https://foo.bar', {
+    method: 'POST',
+    body: JSON.stringify({ foo: 'bar' }),
+  });
+
+  expect(request.headers.get('Content-Type')).toBe('text/plain;charset=UTF-8');
+
+  const next = (req: Request) => {
+    state.request = req;
+    return new Response('ok');
+  };
+
+  const state: { request: Request | null } = {
+    request: null,
+  };
+
+  await middleware(request, next);
+
+  expect(state.request?.headers.get('Content-Type')).toBe(
+    'application/json, text/plain;charset=UTF-8',
+  );
+});

src/middleware/__test__/retry.test.ts

@@ -1,4 +1,4 @@
-import { afterAll, beforeAll, it } from '@std/testing/bdd';
+import { afterAll, beforeAll, test } from '@std/testing/bdd';
 import { expect } from '@std/expect';
 import { applyMiddleware, configureFetch } from '#fetch';
 import { retry } from '../retry.ts';
@@ -22,7 +22,7 @@ afterAll(async () => {
   await server.shutdown();
 });
 
-it('Should fetch resource until it returns success response)', async () => {
+test('Should fetch resource until it returns success response)', async () => {
   const fetch = configureFetch(globalThis.fetch, applyMiddleware(retry({ count: 10 })));
 
   expect(serverState.counter).toBe(3);
@@ -37,7 +37,7 @@ it('Should fetch resource until it returns success response)', async () => {
   await dump(response);
 });
 
-it('Should break fetch loop when attempt limit is reached', async () => {
+test('Should break fetch loop when attempt limit is reached', async () => {
   const fetch = configureFetch(globalThis.fetch, applyMiddleware(retry({ count: 2 })));
 
   serverState.counter = 5;

src/middleware/default-headers.ts

@@ -3,11 +3,13 @@ import type { Middleware } from '#fetch';
 /** Options of default headers middleware. */
 export interface DefaultHeadersOptions {
   /**
-   * How to add header to request headers.
-   * - "set" - headers will be added using "set" method
-   * - "append" - headers will be added using "append" method
+   * How to add headers to request headers.
+   * - "set" - `defaults` will be added to `request.headers` using "set" method
+   * - "append" - `defaults` will be added to `request.headers` using "append" method
+   * - "defaults-set" - `request.headers` will be added to `defaults` using "set" method
+   * - "defaults-append" - `request.headers` will be added to `defaults` using "append" method
    */
-  strategy?: 'set' | 'append';
+  strategy?: 'set' | 'append' | 'defaults-set' | 'defaults-append';
 }
 
 /**
@@ -17,24 +19,52 @@ export interface DefaultHeadersOptions {
  */
 export function defaultHeaders(
   defaults: HeadersInit,
-  { strategy = 'append' }: DefaultHeadersOptions = {},
+  { strategy = 'set' }: DefaultHeadersOptions = {},
 ): Middleware {
   return (request, next) => {
+    /**
+     * Previously, there was a different approach here:
+     * headers were created based on "defaults" argument,
+     * then headers from the request were added to them.
+     *
+     * This was done so that the "default headers" were
+     * truly default and were overridden by what was set by
+     * the developer in the request itself.
+     *
+     * But it didn't work well because browser always
+     * had the "Content-Type" header set by default,
+     * which always overridden the option that was in the
+     * middleware factory arguments.
+     *
+     * To fix this, `strategy` option is introduced.
+     */
+
     // IMPORTANT: for avoid mutate request, just create new Headers and Request here
-    const headers = new Headers(request.headers);
+    const headers = new Headers(strategy.startsWith('defaults-') ? defaults : request.headers);
 
-    /*
-      Previously, there was a different approach here: headers were created based on "defaults" argument, then headers from the request were added to them.
+    if (strategy === 'defaults-set') {
+      request.headers.forEach((value, key) => {
+        headers.set(key, value);
+      });
+    }
 
-      This was done so that the "default headers" were truly default and were overridden by what was set by the developer in the request itself.
+    if (strategy === 'defaults-append') {
+      request.headers.forEach((value, key) => {
+        headers.append(key, value);
+      });
+    }
 
-      But it didn't work well because browser always had the "Content-Type" header set by default, which always overridden the option that was in the middleware factory arguments.
+    if (strategy === 'set') {
+      new Headers(defaults).forEach((value, key) => {
+        headers.set(key, value);
+      });
+    }
 
-      To fix this, default headers are now added to the request headers
-    */
-    new Headers(defaults).forEach((value, key) => {
-      headers[strategy](key, value);
-    });
+    if (strategy === 'append') {
+      new Headers(defaults).forEach((value, key) => {
+        headers.append(key, value);
+      });
+    }
 
     return next(new Request(request, { headers }));
   };