Answers for "complex watch in vuejs"

vue deep watch

watch: {
    colors: {
        handler(newValue){
            console.log('colors changed', newValue)
        }, deep: true
    }
}

vue watch object member

// Use a deep watcher for that:

watch: {
  item: {
     handler(val){
       // do stuff
     },
     deep: true
  }
}