fix: RPC request with id already seen error when using firefox (#91)

Author: ffmcgee725

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- fix: make sure `getUniqueId` is called on each `windowPostMessageTransport` request to avoid `RPC request with id already seen.` error on extension when using firefox ([#91](https://github.com/MetaMask/multichain-api-client/pull/91))
+
 ## [0.10.0]
 
 ### Added

src/transports/windowPostMessageTransport.ts

@@ -28,7 +28,6 @@ export function getWindowPostMessageTransport(
   const { defaultTimeout = DEFAULT_REQUEST_TIMEOUT, warmupTimeout = DEFAULT_WARMUP_TIMEOUT } = params;
   let messageListener: ((event: MessageEvent) => void) | null = null;
   const pendingRequests: Map<number, (value: any) => void> = new Map();
-  let requestId = getUniqueId();
   /**
    * Storing notification callbacks.
    * If we detect a "notification" (a message without an id) coming from the extension, we'll call each callback in here.
@@ -115,7 +114,7 @@ export function getWindowPostMessageTransport(
         throw new TransportError('Transport not connected');
       }
 
-      const id = requestId++;
+      const id = getUniqueId();
       const request = {
         jsonrpc: '2.0' as const,
         id,