$ brew install yarn $ yarn -v yarn install v0.24.6 info No lockfile found. [1/4] 🔍 Resolving packages... [2/4] 🚚 Fetching packages... [3/4] 🔗 Linking dependencies... [4/4] 📃 Building fresh packages... success Saved lockfile. ✨ Done in 14.27s. $ yarn run devserver yarn run v0.24.6 Project is running at http://localhost:3000/ webpack output is served from /