Drop eventsource polyfill to let users opt in to streaming support

.github/workflows/npm_publish.yml

@@ -33,6 +33,8 @@ jobs:
 
       - name: Deprecate the old package
         run: |
-          npm deprecate stellar-sdk@latest "⚠️ This package has moved to @stellar/stellar-sdk! 🚚"
+          V=$(cat package.json | jq '.version' | sed -e 's/\"//g')
+          echo "Deprecating stellar-sdk@$V"
+          npm deprecate stellar-sdk@"<= $V"⚠️ This package has moved to @stellar/stellar-sdk! 🚚"
         env:
           NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}

.github/workflows/tests.yml

@@ -30,7 +30,9 @@ jobs:
         run: yarn install --network-concurrency 1
 
       - name: Build
-        run: yarn build:prod
+        run: |
+          yarn build:prod
+          yarn add --dev eventsource
 
       - name: Unit Tests
         run: yarn test:node

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 they will be opted out of Horizon streaming. This can be done via the [`eventsource`](https://www.npmjs.com/package/eventsource) package, i.e. `npm i eventsource` ([#878](https://github.com/stellar/js-stellar-sdk/pull/878)).
+
 
 ## [v11.1.0](https://github.com/stellar/js-stellar-sdk/compare/v11.0.1...v11.1.0)
 

config/webpack.config.browser.js

@@ -63,17 +63,17 @@ const config = {
     new ESLintPlugin({
       overrideConfigFile: path.resolve(__dirname, '../.eslintrc.js')
     }),
-    // Ignore native modules (sodium-native)
-    new webpack.IgnorePlugin({ resourceRegExp: /sodium-native/ }),
+    // Ignore native modules (sodium-native) and opt-in polyfills
+    new webpack.IgnorePlugin({ resourceRegExp: /(sodium-native|eventsource)/ }),
     new NodePolyfillPlugin({
       includeAliases: ['http', 'https'] // others aren't needed
     }),
     new webpack.ProvidePlugin({
       Buffer: ['buffer', 'Buffer']
-    })
+    }),
   ],
-  watchOptions: {
-    ignored: /(node_modules|coverage|lib|dist)/
+  externals: {
+    'eventsource': ['umd', 'EventSource'],
   }
 };
 

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": "^1.1.15",
     "@types/json-schema": "^7.0.15",
     "@types/lodash": "^4.14.199",
     "@types/mocha": "^10.0.2",
@@ -113,6 +113,7 @@
     "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",
@@ -147,7 +148,6 @@
     "@stellar/stellar-base": "10.0.1",
     "axios": "^1.6.0",
     "bignumber.js": "^9.1.2",
-    "eventsource": "^2.0.2",
     "randombytes": "^2.1.0",
     "toml": "^3.0.0",
     "urijs": "^1.19.1"

src/horizon/call_builder.ts

@@ -19,10 +19,21 @@ 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 ??
-  anyGlobal.window?.EventSource ??
-  require("eventsource");
+// require("eventsource") polyfill for Node and React Native environments
+let EventSource: Constructable<EventSource>;
+try {
+  EventSource = anyGlobal.EventSource ??
+    anyGlobal.window?.EventSource ??
+    require("eventsource");
+} catch (e: any) {
+  console.warn(
+    '⚠️ No EventSource provider found: either polyfill it ' +
+    '(e.g. `npm i eventsource`) or you will not have streaming support.'
+  );
+  console.warn(
+    "⚠️ You can ignore this message if you don't care about streaming."
+  );
+}
 
 /**
  * Creates a new {@link CallBuilder} pointed to server defined by serverUrl.
@@ -110,6 +121,13 @@ export class CallBuilder<
 
     let createEventSource = (): EventSource => {
       try {
+        if (!EventSource) {
+          console.warn(
+            '⚠️ No EventSource provider found: there is no streaming support ' +
+            'unless you polyfill it (e.g. `npm i eventsource`).'
+          );
+        }
+
         es = new EventSource(this.url.toString());
       } catch (err) {
         if (options.onerror) {