[Vuejs]-Set data field from getter and add extra computed field

In situations like this you’ll want the watcher to be run as soon as the component is created. You could move the logic within a method, and then call it from both the watcher and the created hook, but there is a simpler way.

You can use the long-hand version of the watcher in order to pass the immediate: true option. That will make it run instantly as soon as the computed property is resolved.

watch: {
  allMedications: {
    handler: function (val) {
      this.medications = val.map(medication => ({
        ...medication,
        residentName: this.getResidentName(medication.resident)
      });
    },
    immediate: true
  }
}