React Native - make dummy db get real data from api

I am quite new to React Native and JS and have recently purchased a React Native template which has a Dummy DB.

Ideally Id like it to pull data from an external JSON (api) which is being generated from a PHP website we already have running.

Here is the Dummy data file:

import {  DoctorModel,  TreatmentModel,  CampaignModel,  EventModel} from "../models";export const doctorsList: DoctorModel[] = [ { ##JSON HERE## } ];export const treatmentsList: TreatmentModel[] = [ { ##JSON HERE## } ];export const campaignList: CampaignModel[] = [ { ##JSON HERE## } ];export const eventList: EventModel[] = [ { ##JSON HERE## } ];

I want it to export as the same values as above so it will work seamlessly with the current app configuration.

I have tried the following...

export const doctorsList: DoctorModel[] = () =>  fetch(' ##LINK TO API## ')    .then((response) => response.json());

But got this error:

Type '() => Promise<any>' is missing the following properties from type 'DoctorModel[]': pop, push, concat, join, and 27 more.

I have looked all over here and other platforms for a solution but cant find anything.

Again the ideal outcome would for it to work exactly how it would if I manually typed the JSON in as seen in the first code snippet.

Any help is much appreciated, still trying to wrap my head around React! :)