Remove node-fetch.

The package `node-fetch` has been removed, instead requiring that `fetch` be
provided as an option for the fetch middleware.

This might reduce our bundle size (depending on whether our bundler is smart
enough to omit this package already; I'm not sure). It also eliminates a
dependency that has been a source of security advisories in the past.

We will probably want to add it back as a `devDependency` when we add tests
for this middleware, but so far this middleware is not tested.

package.json

@@ -37,7 +37,6 @@
     "eth-rpc-errors": "^4.0.3",
     "json-rpc-engine": "^6.1.0",
     "json-stable-stringify": "^1.0.1",
-    "node-fetch": "^2.6.7",
     "pify": "^3.0.0"
   },
   "devDependencies": {

src/fetch.ts

@@ -7,7 +7,6 @@ import { EthereumRpcError, ethErrors } from 'eth-rpc-errors';
 import type { Block } from './types';
 
 /* eslint-disable @typescript-eslint/no-require-imports,@typescript-eslint/no-shadow */
-const fetch = global.fetch || require('node-fetch');
 const btoa = global.btoa || require('btoa');
 /* eslint-enable @typescript-eslint/no-require-imports,@typescript-eslint/no-shadow */
 
@@ -34,19 +33,27 @@ interface FetchConfig {
   fetchUrl: string;
   fetchParams: Request;
 }
-interface FetchMiddlewareOptions {
-  rpcUrl: string;
-  originHttpHeaderKey?: string;
-}
-
-interface FetchMiddlewareFromReqOptions extends FetchMiddlewareOptions {
-  req: PayloadWithOrigin;
-}
 
+/**
+ * Create middleware for sending a JSON-RPC request to the given RPC URL.
+ *
+ * @param options - Options
+ * @param options.fetch - The `fetch` function; expected to be equivalent to `window.fetch`.
+ * @param options.rpcUrl - The URL to send the request to.
+ * @param options.originHttpHeaderKey - If provider, the origin field for each JSON-RPC request
+ * will be attached to each outgoing fetch request under this header.
+ * @returns The fetch middleware.
+ */
 export function createFetchMiddleware({
+  // eslint-disable-next-line @typescript-eslint/no-shadow
+  fetch,
   rpcUrl,
   originHttpHeaderKey,
-}: FetchMiddlewareOptions): JsonRpcMiddleware<unknown, unknown> {
+}: {
+  fetch: typeof global.fetch;
+  rpcUrl: string;
+  originHttpHeaderKey?: string;
+}): JsonRpcMiddleware<unknown, unknown> {
   return createAsyncMiddleware(async (req, res, _next) => {
     const { fetchUrl, fetchParams } = createFetchConfigFromReq({
       req,
@@ -59,7 +66,7 @@ export function createFetchMiddleware({
     const retryInterval = 1000;
     for (let attempt = 0; attempt < maxAttempts; attempt++) {
       try {
-        const fetchRes: Response = await fetch(fetchUrl, fetchParams);
+        const fetchRes = await fetch(fetchUrl, fetchParams);
         // check for http errrors
         checkForHttpErrors(fetchRes);
         // parse response body
@@ -133,7 +140,11 @@ export function createFetchConfigFromReq({
   req,
   rpcUrl,
   originHttpHeaderKey,
-}: FetchMiddlewareFromReqOptions): FetchConfig {
+}: {
+  rpcUrl: string;
+  originHttpHeaderKey?: string;
+  req: PayloadWithOrigin;
+}): FetchConfig {
   const parsedUrl: URL = new URL(rpcUrl);
   const fetchUrl: string = normalizeUrlFromParsed(parsedUrl);
 

yarn.lock

@@ -880,7 +880,6 @@ __metadata:
     jest: ^27.5.1
     json-rpc-engine: ^6.1.0
     json-stable-stringify: ^1.0.1
-    node-fetch: ^2.6.7
     pify: ^3.0.0
     prettier: ^2.2.1
     prettier-plugin-packagejson: ^2.2.11
@@ -4851,20 +4850,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"node-fetch@npm:^2.6.7":
-  version: 2.6.7
-  resolution: "node-fetch@npm:2.6.7"
-  dependencies:
-    whatwg-url: ^5.0.0
-  peerDependencies:
-    encoding: ^0.1.0
-  peerDependenciesMeta:
-    encoding:
-      optional: true
-  checksum: 8d816ffd1ee22cab8301c7756ef04f3437f18dace86a1dae22cf81db8ef29c0bf6655f3215cb0cdb22b420b6fe141e64b26905e7f33f9377a7fa59135ea3e10b
-  languageName: node
-  linkType: hard
-
 "node-gyp@npm:^7.1.0":
   version: 7.1.2
   resolution: "node-gyp@npm:7.1.2"
@@ -6108,13 +6093,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"tr46@npm:~0.0.3":
-  version: 0.0.3
-  resolution: "tr46@npm:0.0.3"
-  checksum: 726321c5eaf41b5002e17ffbd1fb7245999a073e8979085dacd47c4b4e8068ff5777142fc6726d6ca1fd2ff16921b48788b87225cbc57c72636f6efa8efbffe3
-  languageName: node
-  linkType: hard
-
 "ts-jest@npm:^27.1.4":
   version: 27.1.5
   resolution: "ts-jest@npm:27.1.5"
@@ -6463,13 +6441,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"webidl-conversions@npm:^3.0.0":
-  version: 3.0.1
-  resolution: "webidl-conversions@npm:3.0.1"
-  checksum: c92a0a6ab95314bde9c32e1d0a6dfac83b578f8fa5f21e675bc2706ed6981bc26b7eb7e6a1fab158e5ce4adf9caa4a0aee49a52505d4d13c7be545f15021b17c
-  languageName: node
-  linkType: hard
-
 "webidl-conversions@npm:^5.0.0":
   version: 5.0.0
   resolution: "webidl-conversions@npm:5.0.0"
@@ -6500,16 +6471,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"whatwg-url@npm:^5.0.0":
-  version: 5.0.0
-  resolution: "whatwg-url@npm:5.0.0"
-  dependencies:
-    tr46: ~0.0.3
-    webidl-conversions: ^3.0.0
-  checksum: b8daed4ad3356cc4899048a15b2c143a9aed0dfae1f611ebd55073310c7b910f522ad75d727346ad64203d7e6c79ef25eafd465f4d12775ca44b90fa82ed9e2c
-  languageName: node
-  linkType: hard
-
 "whatwg-url@npm:^8.0.0, whatwg-url@npm:^8.5.0":
   version: 8.7.0
   resolution: "whatwg-url@npm:8.7.0"