Perf: lazy-load more require() calls in main process

Went from 36 unique require calls, to 31 calls after this commit.

src/config.js

@@ -1,5 +1,4 @@
 const appConfig = require('application-config')('WebTorrent')
-const fs = require('fs')
 const path = require('path')
 const electron = require('electron')
 const arch = require('arch')
@@ -146,6 +145,8 @@ function isPortable () {
     return false
   }
 
+  const fs = require('fs')
+
   try {
     // This line throws if the "Portable Settings" folder does not exist, and does
     // nothing otherwise.

src/main/index.js

@@ -124,15 +124,18 @@ function init () {
 function delayedInit () {
   const announcement = require('./announcement')
   const dock = require('./dock')
-  const tray = require('./tray')
   const updater = require('./updater')
   const userTasks = require('./user-tasks')
 
   announcement.init()
   dock.init()
-  tray.init()
   updater.init()
   userTasks.init()
+
+  if (process.platform !== 'darwin') {
+    const tray = require('./tray')
+    tray.init()
+  }
 }
 
 function onOpen (e, torrentId) {

src/main/windows/main.js

@@ -84,11 +84,14 @@ function init (state, options) {
   })
 
   win.on('close', function (e) {
-    const tray = require('../tray')
-
-    if (process.platform !== 'darwin' && !tray.hasTray()) {
-      app.quit()
-    } else if (!app.isQuitting) {
+    if (process.platform !== 'darwin') {
+      const tray = require('../tray')
+      if (!tray.hasTray()) {
+        app.quit()
+        return
+      }
+    }
+    if (!app.isQuitting) {
       e.preventDefault()
       hide()
     }
@@ -226,17 +229,21 @@ function toggleFullScreen (flag) {
 }
 
 function onWindowBlur () {
-  const tray = require('../tray')
-
   menu.setWindowFocus(false)
-  tray.setWindowFocus(false)
+
+  if (process.platform !== 'darwin') {
+    const tray = require('../tray')
+    tray.setWindowFocus(false)
+  }
 }
 
 function onWindowFocus () {
-  const tray = require('../tray')
-
   menu.setWindowFocus(true)
-  tray.setWindowFocus(true)
+
+  if (process.platform !== 'darwin') {
+    const tray = require('../tray')
+    tray.setWindowFocus(true)
+  }
 }
 
 function getIconPath () {

src/renderer/lib/state.js

@@ -1,10 +1,8 @@
 const appConfig = require('application-config')('WebTorrent')
-const debounce = require('debounce')
 const path = require('path')
 const {EventEmitter} = require('events')
 
 const config = require('../../config')
-const migrations = require('./migrations')
 
 const SAVE_DEBOUNCE_INTERVAL = 1000
 
@@ -12,7 +10,14 @@ const State = module.exports = Object.assign(new EventEmitter(), {
   getDefaultPlayState,
   load,
   // state.save() calls are rate-limited. Use state.saveImmediate() to skip limit.
-  save: debounce(saveImmediate, SAVE_DEBOUNCE_INTERVAL),
+  save: function () {
+    // Perf optimization: Lazy-require debounce (and it's dependencies)
+    const debounce = require('debounce')
+    // After first State.save() invokation, future calls go straight to the
+    // debounced function
+    State.save = debounce(saveImmediate, SAVE_DEBOUNCE_INTERVAL)
+    State.save()
+  },
   saveImmediate
 })
 
@@ -205,7 +210,13 @@ function load (cb) {
     if (err) return cb(err)
     const state = getDefaultState()
     state.saved = saved
-    migrations.run(state)
+
+    if (process.type === 'renderer') {
+      // Perf optimization: Save require() calls in the main process
+      const migrations = require('./migrations')
+      migrations.run(state)
+    }
+
     cb(null, state)
   }
 }