I set up Theia with the following on a Macbook:
sudo port install npm6
sudo port install nvm
sudo npm install -g yo generator-theia-extension
sudo npm install -g theia
mkdir theia-hello-world-extension
cd theia-hello-world-extension
yo theia-extension # select the 'Hello World' option and complete the prompts
nvm install 10
nvm use 10
yarn start:browser
And it does 'stuff' but doesn't start ... nothing running on port 3000, desktop app doesn't do anything either. This is all I get:
yarn start:browser
yarn run v1.22.19
$ yarn rebuild:browser && yarn --cwd browser-app start
$ theia rebuild:browser
$ theia start
✨ Done in 3.83s.
yarn start:electron
yarn run v1.22.19
$ yarn rebuild:electron && yarn --cwd electron-app start
$ theia rebuild:electron
$ theia start
✨ Done in 3.96s.