perf(lnd): run lnd integration in web workers

fix LN-Zap#1990

electron/main.js

@@ -244,6 +244,7 @@ app.on('ready', async () => {
     backgroundColor: get(theme, 'colors.primaryColor', '#242633'),
     webPreferences: {
       nodeIntegration: false,
+      nodeIntegrationInWorker: true,
       preload: isDev
         ? path.resolve(__dirname, '..', 'dist', 'preload.js')
         : path.resolve(__dirname, 'preload.js'),

electron/preload.js

@@ -14,8 +14,11 @@ import config from 'config'
 import { getDb } from '@zap/renderer/store/db'
 import isSubDir from '@zap/utils/isSubDir'
 import { getAllLocalWallets } from '@zap/utils/localWallets'
+import lndBinaryPath from '@zap/utils/lndBinaryPath'
+import lndGrpcProtoPath from '@zap/utils/lndGrpcProtoPath'
 import validateHost from '@zap/utils/validateHost'
 import { getDbName } from '@zap/utils/db'
+import LndConfig from '@zap/utils/lndConfig'
 
 const fsReadFile = promisify(fs.readFile)
 const fsRimraf = promisify(rimraf)
@@ -68,10 +71,35 @@ function openTestnetFaucet() {
 function killLnd() {
   return new Promise(resolve => {
     ipcRenderer.once('killLndSuccess', resolve)
-    ipcRenderer.send('killLnd', { signal: 'SIGKILL', timeout: 2500 })
+    ipcRenderer.send('killLnd')
   })
 }
 
+/**
+ * Generates an lnd config object from a wallet config.
+ * @param  {Object} wallet Wallet config
+ * @return {Object}        Lnd config
+ */
+async function generateLndConfigFromWallet(wallet) {
+  // Convert wallet config to lnd config.
+  wallet.decoder = wallet.decoder || 'lnd.lndconnect.v1'
+  let lndConfig = new LndConfig({
+    ...wallet,
+    userDataDir: getUserDataDir(),
+    binaryPath: lndBinaryPath(),
+    protoPath: lndGrpcProtoPath(),
+  })
+
+  // Wait for the config to become fully initialized.
+  await lndConfig.isReady
+
+  // Flatten the config into a plan object so we can pass it between services.
+  // We can not pass a Promise to the Web Worker, so replace with true value.
+  lndConfig = Object.assign({}, lndConfig, { isReady: true })
+
+  return lndConfig
+}
+
 /**
  * Returns specified wallet files location
  * @param {*} chain
@@ -158,6 +186,7 @@ window.Zap = {
   openExternal,
   openHelpPage,
   openTestnetFaucet,
+  generateLndConfigFromWallet,
   getWalletDir,
   getAllLocalWallets,
   deleteLocalWallet,