Make eventsource an optional dependency for streamers

CHANGELOG.md

@@ -5,6 +5,9 @@ A breaking change will get clearly marked in this log.
 
 ## Unreleased
 
+### Breaking Changes
+* Downstream consumers must now polyfill an `EventSource` provider if they do not have native support or must opt-out of Horizon streaming support. This can be done via the [`eventsource`](https://www.npmjs.com/package/eventsource) package ([TODO]()).
+
 
 ## [v11.0.0-beta.6](https://github.com/stellar/js-stellar-sdk/compare/v11.0.0-beta.5...v11.0.0-beta.6)
 

package.json

@@ -88,7 +88,7 @@
     "@stellar/tsconfig": "^1.0.2",
     "@types/chai": "^4.3.6",
     "@types/detect-node": "^2.0.0",
-    "@types/eventsource": "^1.1.12",
+    "@types/eventsource": "^1.1.14",
     "@types/lodash": "^4.14.199",
     "@types/mocha": "^10.0.2",
     "@types/node": "^20.8.10",
@@ -112,6 +112,7 @@
     "eslint-plugin-prefer-import": "^0.0.1",
     "eslint-plugin-prettier": "^5.0.0",
     "eslint-webpack-plugin": "^4.0.1",
+    "eventsource": "^2.0.2",
     "ghooks": "^2.0.4",
     "husky": "^8.0.3",
     "jsdoc": "^4.0.2",
@@ -144,7 +145,6 @@
   "dependencies": {
     "axios": "^1.6.0",
     "bignumber.js": "^9.1.2",
-    "eventsource": "^2.0.2",
     "randombytes": "^2.1.0",
     "stellar-base": "10.0.0-beta.4",
     "toml": "^3.0.0",

src/horizon/call_builder.ts

@@ -20,9 +20,14 @@ export interface EventSourceOptions<T> {
 const anyGlobal = global as any;
 type Constructable<T> = new (e: string) => T;
 // require("eventsource") for Node and React Native environment
-let EventSource: Constructable<EventSource> = anyGlobal.EventSource ??
+const EventSource: Constructable<EventSource> = anyGlobal.EventSource ??
   anyGlobal.window?.EventSource ??
   require("eventsource");
+if (!EventSource) {
+  console.warn(
+    '⚠️ No EventSource provider found: either polyfill it (e.g. `npm i eventsource`) or you will not have streaming support.'
+  );
+}
 
 /**
  * Creates a new {@link CallBuilder} pointed to server defined by serverUrl.

yarn.lock

@@ -1423,7 +1423,7 @@
   resolved "https://registry.yarnpkg.com/@types/estree/-/estree-1.0.4.tgz#d9748f5742171b26218516cf1828b8eafaf8a9fa"
   integrity sha512-2JwWnHK9H+wUZNorf2Zr6ves96WHoWDJIftkcxPKsS7Djta6Zu519LarhRNljPXkpsZR2ZMwNCPeW7omW07BJw==
 
-"@types/eventsource@^1.1.12":
+"@types/eventsource@^1.1.14":
   version "1.1.14"
   resolved "https://registry.yarnpkg.com/@types/eventsource/-/eventsource-1.1.14.tgz#b5b115b19f3a392a6c29331486bc88dcb4e8a4e2"
   integrity sha512-WiPIkZ5fuhTkeaVaPKbaP6vHuTX9FHnFNTrkSbm+Uf6g4TH3YNbdfw5/1oLzKIWsQRbrvSiByO2nPSxjr5/cgQ==