Sending data between window instances with Electron.

alice.js

const { ipcRenderer } = require('electron')

ipcRenderer.on('postal-error',(event, errorPayload)=>{
  const {
    error,
    sender,
    destination,
    payload
  } = errorPayload
  
  console.error('[Postal Error]', errorPayload)
})

// Let's get cute.

const hiYouCanCallMe = (sender) => {
  ipcRenderer.send('register-letter-address', sender)
  return (destination) => (payload) => ipcRenderer.send('send-letter', {sender,destination,payload})
}
const whenALetterArrivesFrom = (sender) => (callback) => ipcRenderer.on('letter-from-${sender}', callback)

// Now, I think I'll call this intance Alice.

const sendLettersTo = hiYouCanCallMe('Alice')

// Rachael has a friend named Alice, another window instance.

const sendLetterToRachael = sendLettersTo('Rachael')

// Yay! 

sendToRachael({
  title:"Hello! Long time no see!",
  body:"It has been over three years since the shipwreck, but..."
})

// We like this person

const whenFromRachael = whenALetterArrivesFrom('Rachael')

whenFromRachael((event, payload)=>{
  /*
  read()
  reply()
  keepForLater()
  */
})

// We don't like this person.

const burnInABonfire = (event, payload) => {}

const whenFromJames = whenALetterArrivesFrom('James')

whenFromJames(burnInABonfire)

main.js

const {ipcMain} = require('electron')

ipcMain.on('register-letter-address', ( event, { name })=>{ AddressMap.set(name,event.sender) })
ipcMain.on('send-letter',(event, { sender, destination, payload })=>{
	if(AddressMap.has(destination)){
		destination.send(`letter-from-${sender}`, payload)
	}else{
		event.sender.send(`postal-error`,{
			error:'unknown-destination',
			destination,
			sender,
			payload
		})
	}
})