Add avoidCors API to EdgeFetchFunction

This is to be able to to access `nativeFetch` in React Native
environments. This parameter consolidates all fetch modes into one
method.

Setting `auto` (default) will act like old `fetchCors` method.

Setting `always` will act like old `fetch` method.

Setting `never` will forcibly use the CORS-safe fetching implementation
(cors-servers in browser environments and `nativeFetch` in React Native
environments).

In Node environments, `never`, `auto` and `always` are
all idempotent.

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- added: Added `fetchCorsForced` for access to nativeFetch in React Native.
+
 ## 2.21.0 (2024-12-02)
 
 - added: Added `networkFees` to `EdgeTransaction`.

src/io/browser/browser-io.ts

@@ -39,13 +39,19 @@ export function makeBrowserIo(): EdgeIo {
     }),
 
     // Networking:
-    fetch(uri: string, opts?: EdgeFetchOptions): Promise<EdgeFetchResponse> {
-      return window.fetch(uri, opts)
-    },
-    async fetchCors(
+    async fetch(
       uri: string,
       opts?: EdgeFetchOptions
     ): Promise<EdgeFetchResponse> {
+      const { avoidCors = 'auto' } = opts ?? {}
+
+      if (avoidCors === 'never') {
+        return await fetchCorsProxy(uri, opts)
+      }
+      if (avoidCors === 'always') {
+        return await window.fetch(uri, opts)
+      }
+
       const { hostname } = new URL(uri)
       const corsFailureCount = hostnameCorsProxyBlacklist.get(hostname) ?? 0
 
@@ -90,6 +96,13 @@ export function makeBrowserIo(): EdgeIo {
       // Throw the error from the first fetch instead of the one from
       // proxy server.
       throw errorToThrow
+    },
+
+    async fetchCors(
+      uri: string,
+      opts?: EdgeFetchOptions
+    ): Promise<EdgeFetchResponse> {
+      return await this.fetch(uri, opts)
     }
   }
 }

src/io/react-native/react-native-worker.ts

@@ -172,13 +172,15 @@ async function makeIo(): Promise<EdgeIo> {
       uri: string,
       opts?: EdgeFetchOptions
     ): Promise<EdgeFetchResponse> {
-      return await window.fetch(uri, opts)
-    },
+      const { avoidCors = 'auto' } = opts ?? {}
+
+      if (avoidCors === 'never') {
+        return await nativeFetch(uri, opts)
+      }
+      if (avoidCors === 'always') {
+        return await window.fetch(uri, opts)
+      }
 
-    async fetchCors(
-      uri: string,
-      opts: EdgeFetchOptions = {}
-    ): Promise<EdgeFetchResponse> {
       const { protocol, host, pathname } = new URL(uri)
       const endpoint = `${protocol}//${host}${pathname}`
       const state = endpointCorsState.get(endpoint) ?? {
@@ -208,6 +210,13 @@ async function makeIo(): Promise<EdgeIo> {
       const response = await nativeFetch(uri, opts)
       state.nativeSuccess = true
       return response
+    },
+
+    async fetchCors(
+      uri: string,
+      opts: EdgeFetchOptions = {}
+    ): Promise<EdgeFetchResponse> {
+      return await this.fetch(uri, opts)
     }
   }
 

src/types/types.ts

@@ -76,6 +76,8 @@ export interface EdgeIo {
   /**
    * This is like `fetch`, but will try to avoid CORS limitations
    * on platforms where that may be a problem.
+   *
+   * @deprecated - Use `fetch` instead with `avoidCors: 'always'` option.
    */
   readonly fetchCors: EdgeFetchFunction
 }