Electron global variable garbage collected if renderer process closes?

In Electron, I have my main process opening a BrowserWindow. The BrowserWindow loads one html page and then the same window eventually loads another html page.


var mainWindow;
global.mainState = {
  settings: {}
mainWindow = createWindow('main', {
  width: 1000,
  height: 800,
if (curState == 'load') {
  mainWindow.loadURL(`file://${__dirname}/interface/load.html`, {})
if (curState == 'login') {
  mainWindow.loadURL(`file://${__dirname}/interface/login.html`, {})


const remote = require('electron').remote;
var testGlobal = remote.getGlobal('mainState')
testGlobal.settings = 'test value'
testGlobal.settings.inner = 'test value2'

When main.js loads the second page (login.html), will the global variable be deleted/dereferenced? The docs say that if the renderer process dereferences a global variable then the variable will be gc'd. When I try to test this I get inconsistent results and I would just like some explanation from someone more wise than I.



testGlobal will be garbage collected, since the site changes. global.mainState will not be deleted, however it will also not change when you call testGlobal.settings = 'test value', because remote.getGlobal() just gives you a copy of mainState and not a reference.

I would suggest you use ipcMain and ipcRenderer to sync the global variable yourself.


Use IPC to Set the Global's Value.

@RoyalBingBong is correct in that "remote.getGlobal() just gives you a copy of mainState and not a reference."

It might seems like you're changing the value of the global variable, but you're not. So, for example, when I refresh my Electron browser window, the value of that global variable would revert to what it was.

I found that the only way to properly change the value of the global variable was to use ipcMain and ipcRenderer (the verbose way).


const { ipcMain } = require( "electron" );

ipcMain.on( "setMyGlobalVariable", ( event, myGlobalVariable ) => {
  global.myGlobalVariable = myGlobalVariable;
} );


const { ipcRenderer, remote } = require( "electron" );

// Set MyGlobalVariable.
ipcRenderer.send( "setMyGlobalVariable", "Hi There!" );

// Read MyGlobalVariable.
remote.getGlobal( "MyGlobalVariable" ); // => "Hi There!"

Now, I can refresh my Electron window or spin up a new renderer process and value of the global variable will correctly be what I set it to, in this example, "Hi There!".

You can also see that for reading it, I use the simpler remote.getGlobal. I haven't tested whether this will cause problems when the value changes and the value of this doesn't get updated. I might have to come back to this answer if that's the case and use another ipcMain and ipcRenderer to manually read the global variable.


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