feat: add an option to configure the fetch impl (#342)

README.md

@@ -109,6 +109,11 @@ gaxios.request({url: '/data'}).then(...);
   // status code.  Defaults to (>= 200 && < 300)
   validateStatus: (status: number) => true,
 
+  // Implementation of `fetch` to use when making the API call. By default,
+  // will use the browser context if available, and fall back to `node-fetch`
+  // in node.js otherwise.
+  fetchImplementation?: typeof fetch;
+
   // Configuration for retrying of requests.
   retryConfig: {
     // The number of times to retry the request.  Defaults to 3.

browser-test/.eslintrc.json

@@ -0,0 +1,5 @@
+{
+  "env": {
+    "browser": true
+  }
+}

browser-test/test.browser.ts

@@ -33,6 +33,14 @@ describe('💻 browser tests', () => {
     assert.strictEqual(result.data, 'value');
   });
 
+  it('should allow passing browser fetch explicitly', async () => {
+    const result = await request({
+      url: `http://localhost:${port}/path`,
+      fetchImplementation: window.fetch,
+    });
+    assert.strictEqual(result.status, 200);
+  });
+
   it('should support multipart post from the browser', async () => {
     const headers: {[key: string]: string} = {};
     const multipart = [

package.json

@@ -11,7 +11,7 @@
     "lint": "gts check",
     "test": "c8 mocha build/test",
     "presystem-test": "npm run compile",
-    "system-test": "mocha build/system-test --timeout 40000",
+    "system-test": "mocha build/system-test --timeout 80000",
     "compile": "tsc -p .",
     "fix": "gts fix",
     "prepare": "npm run compile",
@@ -50,15 +50,12 @@
     "@types/multiparty": "0.0.32",
     "@types/mv": "^2.1.0",
     "@types/ncp": "^2.0.1",
-    "@types/nock": "^10.0.0",
     "@types/node": "^11.9.5",
-    "@types/node-fetch": "^2.1.6",
+    "@types/node-fetch": "^2.5.7",
     "@types/sinon": "^9.0.0",
     "@types/tmp": "0.2.0",
     "@types/uuid": "^8.0.0",
     "c8": "^7.0.0",
-    "chai": "^4.2.0",
-    "codecov": "^3.2.0",
     "cors": "^2.8.5",
     "execa": "^4.0.0",
     "express": "^4.16.4",

samples/package.json

@@ -8,11 +8,10 @@
     "test": "mocha"
   },
   "license": "Apache-2.0",
-  "devDependencies": {
-    "chai": "^4.2.0",
-    "mocha": "^8.0.0"
-  },
   "dependencies": {
     "gaxios": "^4.0.1"
+  },
+  "devDependencies": {
+    "mocha": "^8.0.0"
   }
 }

samples/test/test.samples.js

@@ -13,14 +13,14 @@
 // limitations under the License.
 
 const {execSync} = require('child_process');
-const {assert} = require('chai');
+const assert = require('assert');
 const {describe, it} = require('mocha');
 
 const exec = cmd => execSync(cmd, {encoding: 'utf8'});
 
 describe(__filename, () => {
   it('should run the quickstart', () => {
     const output = exec('node quickstart');
-    assert.include(output, 'status: 200');
+    assert.ok(output.includes('status: 200'));
   });
 });

src/common.ts

@@ -99,6 +99,12 @@ export interface GaxiosOptions {
   retry?: boolean;
   signal?: AbortSignal;
   size?: number;
+  /**
+   * Implementation of `fetch` to use when making the API call. By default,
+   * will use the browser context if available, and fall back to `node-fetch`
+   * in node.js otherwise.
+   */
+  fetchImplementation?: FetchImplementation;
 }
 
 /**
@@ -147,3 +153,38 @@ export interface RetryConfig {
    */
   noResponseRetries?: number;
 }
+
+export type FetchImplementation = (
+  input: FetchRequestInfo,
+  init?: FetchRequestInit
+) => Promise<FetchResponse>;
+
+export type FetchRequestInfo = any;
+
+export interface FetchResponse {
+  readonly status: number;
+  readonly statusText: string;
+  readonly url: string;
+  readonly body: unknown | null;
+  arrayBuffer(): Promise<unknown>;
+  blob(): Promise<unknown>;
+  readonly headers: FetchHeaders;
+  json(): Promise<any>;
+  text(): Promise<string>;
+}
+
+export interface FetchRequestInit {
+  method?: string;
+}
+
+export interface FetchHeaders {
+  append(name: string, value: string): void;
+  delete(name: string): void;
+  get(name: string): string | null;
+  has(name: string): boolean;
+  set(name: string, value: string): void;
+  forEach(
+    callbackfn: (value: string, key: string) => void,
+    thisArg?: any
+  ): void;
+}

src/gaxios.ts

@@ -13,12 +13,13 @@
 
 import extend from 'extend';
 import {Agent} from 'http';
-import nodeFetch, {Response as NodeFetchResponse} from 'node-fetch';
+import nodeFetch from 'node-fetch';
 import qs from 'querystring';
 import isStream from 'is-stream';
 import url from 'url';
 
 import {
+  FetchResponse,
   GaxiosError,
   GaxiosOptions,
   GaxiosPromise,
@@ -28,7 +29,6 @@ import {
 import {getRetryConfig} from './retry';
 
 /* eslint-disable @typescript-eslint/no-explicit-any */
-/* eslint-disable node/no-unsupported-features/node-builtins */
 
 const fetch = hasFetch() ? window.fetch : nodeFetch;
 
@@ -88,7 +88,8 @@ export class Gaxios {
   private async _defaultAdapter<T>(
     opts: GaxiosOptions
   ): Promise<GaxiosResponse<T>> {
-    const res = await fetch(opts.url!, opts);
+    const fetchImpl = opts.fetchImplementation || fetch;
+    const res = (await fetchImpl(opts.url!, opts)) as FetchResponse;
     const data = await this.getResponseData(opts, res);
     return this.translateResponse<T>(opts, res, data);
   }
@@ -130,7 +131,7 @@ export class Gaxios {
 
   private async getResponseData(
     opts: GaxiosOptions,
-    res: Response | NodeFetchResponse
+    res: FetchResponse
   ): Promise<any> {
     switch (opts.responseType) {
       case 'stream':
@@ -250,7 +251,7 @@ export class Gaxios {
 
   private translateResponse<T>(
     opts: GaxiosOptions,
-    res: Response | NodeFetchResponse,
+    res: FetchResponse,
     data?: T
   ): GaxiosResponse<T> {
     // headers need to be converted from a map to an obj

test/test.getch.ts

@@ -16,6 +16,7 @@ import nock from 'nock';
 import sinon from 'sinon';
 import stream from 'stream';
 import {describe, it, afterEach} from 'mocha';
+import fetch from 'node-fetch';
 // eslint-disable-next-line @typescript-eslint/no-var-requires
 const HttpsProxyAgent = require('https-proxy-agent');
 import {
@@ -277,6 +278,13 @@ describe('🥁 configuration options', () => {
     scope.done();
     assert.deepStrictEqual(res.config.data, body);
   });
+
+  it('should allow explicitly setting the fetch implementation to node-fetch', async () => {
+    const scope = nock(url).get('/').reply(200);
+    const res = await request({url, fetchImplementation: fetch});
+    scope.done();
+    assert.deepStrictEqual(res.status, 200);
+  });
 });
 
 describe('🎏 data handling', () => {