Dougie Richardson – Page 7 – Every day is a school day

Expo on Codespaces

GitHub account (free individual accounts have 60 hours of free Codespaces each month).
Expo account.
Expo Go app installed on your device.
A little knowledge of the command line and React programming.

About ten minutes.

Create a new Codespace using the blank template:

Once initalised, create an empty Expo React App (select (y)es when prompted):

npx create-expo-app example

Install the expo-cli command line tool globally:

npm install -g expo-cli

Change into your example project’s folder and edit App.js, maybe adding an image or whatever, before updating packages:

cd example
npm update

Login to your Expo account from the command line:

Create an account with Expo and login using the expo login command.

Expo-cli supports tunnelling, a proxy URL accesible from any device over the Internet, using ngrok.

expo start --tunnel

After installing the requested library (@expo/ngrok@^4.1.0), you should see a QR code:

Open the Expo Go app on your device, login, and then scan the QR code. The app will bundle and be available on your device.

Expected behaviour:

npm run android

Should launch Metro and an Android emulator but Metro is not launched. Manually launching metro works:

npm start

Windows might generate a /etc/resolv.conf with an incorrect nameserver while installing Windows Subsystem for Linux (WSL).

It’s a quick fix – edit /etc/resolv.conf and change the nameserver (Google’s is 8.8.8.8).

To prevent it being overwritten, create or edit /etc/wsl.conf adding the option generateResolvConf = false.