Andrew Rhodes

Andrew Rhodes


COVID-19 Symptom Study Tracker with React Native

COVID-19 Symptom Study

About The Project

COVID Symptom Study is an open source Android and iOS app whose goal is to stop the spread of COVID-19 disease and help identify people who are at risk sooner.

The COVID Symptom Study was designed by doctors and scientists at King’s College London, Guys and St Thomas’ Hospitals working in partnership with ZOE Global Ltd – a health science company.

If you’re doing research on COVID-19 and you want to contribute or believe this initiative can help your efforts, please let us know at

Built With

Getting Started

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.


  • npm
  • expo-cli
npm install npm@latest -g
npm install expo-cli --g


  1. Clone the repo

    git clone
  2. When you first start your application you should see the IP address in the console (located above the QR code). For example:

  3. Create a .env file - please note that http:// is required otherwise API requests will fail.

    echo "API_URL=http://<ip_address_host_here>:3000" > .env


    echo "API_URL=http://123.456.7.890:3000" > .env

    NOTE: if you change the .env file be sure to clear the metro cache to ensure your changes take place.

    rm -rf $TMPDIR/metro-*


    expo clear-metro-cache
  4. Run the following command to create AMPLITUDE_KEY environment variable:

    echo "AMPLITUDE_KEY=test_key" >> .env
  5. Create an empty ./google-services.json file in the root of the application.

    echo "{}" > google-services.json
  6. Run the following commands

    npm install
    expo start
  7. Run the mock server

    npm run mock-server
    • note: Mock server is currently unavailble (using)

Git Hooks

The git hook checks can be manually disabled calling git commit and git push with the --no-verify flag if needed.


  1. Run the standard suite of integration tests

    npm test
  2. Check the i18n strings for a locale are complete

    npm test:i18n sv-SE


We are trying to embrace Component Driven Design. To develop

  1. Set ENABLE_STORYBOOK=true in App.tsx

  2. Start the storybook server with npm run storybook. This will open a webpage where you can flip through the stories in this project, after you’ve connected a iOS or Android device via expo start.


See the open issues for a list of proposed features (and known issues).


Contributions are what make the open source community such an amazing place to be learn, inspire, and create. Any contributions you make are greatly appreciated - see the contributing guidelines.

  1. Fork the Project
  2. Create your Feature Branch (git checkout -b feature/AmazingFeature)
  3. Commit your Changes (git commit -m 'Add some AmazingFeature')
  4. Push to the Branch (git push origin feature/AmazingFeature)
  5. Open a Pull Request

Common Issues

These are some known, common issues and their solutions:

  1. Changes to .env don’t get picked up.
  • Solution: Change some of the source code or restart the expo project running expo start -c
  1. Unable to resolve module deprecated-react-native-listview
  • Solution: Running rm -rf $TMPDIR/metro-cache has been reported to solve the problem.
  1. Sometimes when working with React Native a total reset is required to get things up and running again. There can be lots of reasons for this and some googling may be required, however, the following is a common approach that works for many instances:
watchman watch-del-all && rm package-lock.json && rm -rf node_modules && rm -rf $TMPDIR/metro-* && rm -rf $TMPDIR/haste-map-* && npm install

or run

expo reset

Multiple iOS simulators

How to run multiple ios simulators with expo


Distributed under the Apache 2.0 License. See LICENSE for more information.


ZOE Engineering -


Download Details:

Author: zoe

Source Code:

#react-native #react #mobile-apps

What is GEEK

Buddha Community

COVID-19 Symptom Study Tracker with React Native
Autumn  Blick

Autumn Blick


How native is React Native? | React Native vs Native App Development

If you are undertaking a mobile app development for your start-up or enterprise, you are likely wondering whether to use React Native. As a popular development framework, React Native helps you to develop near-native mobile apps. However, you are probably also wondering how close you can get to a native app by using React Native. How native is React Native?

In the article, we discuss the similarities between native mobile development and development using React Native. We also touch upon where they differ and how to bridge the gaps. Read on.

A brief introduction to React Native

Let’s briefly set the context first. We will briefly touch upon what React Native is and how it differs from earlier hybrid frameworks.

React Native is a popular JavaScript framework that Facebook has created. You can use this open-source framework to code natively rendering Android and iOS mobile apps. You can use it to develop web apps too.

Facebook has developed React Native based on React, its JavaScript library. The first release of React Native came in March 2015. At the time of writing this article, the latest stable release of React Native is 0.62.0, and it was released in March 2020.

Although relatively new, React Native has acquired a high degree of popularity. The “Stack Overflow Developer Survey 2019” report identifies it as the 8th most loved framework. Facebook, Walmart, and Bloomberg are some of the top companies that use React Native.

The popularity of React Native comes from its advantages. Some of its advantages are as follows:

  • Performance: It delivers optimal performance.
  • Cross-platform development: You can develop both Android and iOS apps with it. The reuse of code expedites development and reduces costs.
  • UI design: React Native enables you to design simple and responsive UI for your mobile app.
  • 3rd party plugins: This framework supports 3rd party plugins.
  • Developer community: A vibrant community of developers support React Native.

Why React Native is fundamentally different from earlier hybrid frameworks

Are you wondering whether React Native is just another of those hybrid frameworks like Ionic or Cordova? It’s not! React Native is fundamentally different from these earlier hybrid frameworks.

React Native is very close to native. Consider the following aspects as described on the React Native website:

  • Access to many native platforms features: The primitives of React Native render to native platform UI. This means that your React Native app will use many native platform APIs as native apps would do.
  • Near-native user experience: React Native provides several native components, and these are platform agnostic.
  • The ease of accessing native APIs: React Native uses a declarative UI paradigm. This enables React Native to interact easily with native platform APIs since React Native wraps existing native code.

Due to these factors, React Native offers many more advantages compared to those earlier hybrid frameworks. We now review them.

#android app #frontend #ios app #mobile app development #benefits of react native #is react native good for mobile app development #native vs #pros and cons of react native #react mobile development #react native development #react native experience #react native framework #react native ios vs android #react native pros and cons #react native vs android #react native vs native #react native vs native performance #react vs native #why react native #why use react native

Juned Ghanchi


React Native App Developers India, React Native App Development Company

Expand your user base by using react-native apps developed by our expert team for various platforms like Android, Android TV, iOS, macOS, tvOS, the Web, Windows, and UWP.

We help businesses to scale up the process and achieve greater performance by providing the best react native app development services. Our skilled and experienced team’s apps have delivered all the expected results for our clients across the world.

To achieve growth for your business, hire react native app developers in India. You can count on us for all the technical services and support.

#react native app development company india #react native app developers india #hire react native developers india #react native app development company #react native app developers #hire react native developers

Hire Dedicated React Native Developer

Have you ever thought of having your own app that runs smoothly over multiple platforms?

React Native is an open-source cross-platform mobile application framework which is a great option to create mobile apps for both Android and iOS. Hire Dedicated React Native Developer from top React Native development company, to design a spectacular React Native application for your business.

Consult with experts:-

#hire dedicated react native developer #react native development company #react native development services #react native development #react native developer #react native

Hire Dedicated React Native Developers - WebClues Infotech

Being one of the emerging frameworks for app development the need to develop react native apps has increased over the years.

Looking for a react native developer?

Worry not! WebClues infotech offers services to Hire React Native Developers for your app development needs. We at WebClues Infotech offer a wide range of Web & Mobile App Development services based o your business or Startup requirement for Android and iOS apps.

WebClues Infotech also has a flexible method of cost calculation for hiring react native developers such as Hourly, Weekly, or Project Basis.

Want to get your app idea into reality with a react native framework?

Get in touch with us.

Hire React Native Developer Now:

For inquiry:


#hire react native developers #hire dedicated react native developers #hire react native developer #hiring a react native developer #hire freelance react native developers #hire react native developers in 1 hour

Factors affecting the cost of hiring a React Native developer in USA -

Want to develop app using React Native? Here are the tips that will help to reduce the cost of react native app development for you.
Cost is a major factor in helping entrepreneurs take decisions about investing in developing an app and the decision to hire react native app developers in USA can prove to be fruitful in the long run. Using react native for app development ensures a wide range of benefits to your business. Understanding your business and working on the aspects to strengthen business processes through a cost-efficient mobile app will be the key to success.

#best react native development companies from the us #top react native app development companies in usa #cost of hiring a react native developer in usa #top-notch react native developer in usa #best react native developers usa #react native