Re-added code to clean branch

content/_code-samples/build-a-wallet/desktop-js/view/1_preload.js

@@ -0,0 +1,11 @@
+const { contextBridge, ipcRenderer } = require('electron');
+
+// Expose functionality from main process (aka. "backend") to be used by the renderer process(aka. "backend")
+contextBridge.exposeInMainWorld('electronAPI', {
+    // By calling "onUpdateLedgerIndex" in the frontend process we can now attach a callback function to
+    // by making onUpdateLedgerIndex available at the window level.
+    // The subscribed function gets triggered whenever the backend process triggers the event 'update-ledger-index'
+    onUpdateLedgerIndex: (callback) => {
+        ipcRenderer.on('update-ledger-index', callback)
+    }
+})