Example JXA script to kick off multiple terminal processes

example.js

#!/usr/bin/env osascript -l JavaScript

/*
  osascript -l JavaScript <this-file.js>

  see https://github.com/JXA-Cookbook/JXA-Cookbook/wiki/
*/

const System = Application('System Events')
const Terminal = Application('Terminal')

function message(msg) {
  console.log('🧟 ' + msg)
}

function currentWindow() {
  return Terminal.windows().find(win => win.frontmost() === true)
}

Terminal.activate()

const tabs = {
  master: currentWindow(),
  one: null,
  two: null
}

message('Spawning tabs')

System.keystroke('t', {
  using: 'command down'
})
tabs.one = currentWindow()

System.keystroke('t', {
  using: 'command down'
})
tabs.two = currentWindow()

// re-focus initial tab
tabs.master.frontmost = true

message('Starting app one')
Terminal.doScript('cd ~/', {
  in: tabs.one
})
Terminal.doScript('echo "whatever"', {
  in: tabs.one
})

message('Starting app two')
Terminal.doScript('cd ~/', {
  in: tabs.two
})
Terminal.doScript('echo "another"', {
  in: tabs.two
})

message('Done')