firebase-tools: Deployment error: yarn_install is likely not on the path

Version info

5.1.1

Platform Information

OSX

Steps to reproduce

Running firebase deploy to deploy the website.

Expected behavior

Website deployed on firebase hosting

Actual behavior

i  deploying functions, hosting
i  functions: ensuring necessary APIs are enabled...
✔  functions: all necessary APIs are enabled
i  functions: preparing functions directory for uploading...
i  functions: packaged functions (1.28 MB) for uploading
✔  functions: functions folder uploaded successfully
i  hosting[opweb-staging]: beginning deploy...
i  hosting[opweb-staging]: found 65 files in public
✔  hosting[opweb-staging]: file upload complete
i  functions: updating Node.js 8 function opweb(us-central1)...
⚠  functions[opweb(us-central1)]: Deployment error.
Build failed: {"message": "yarn_install yarn install --production\nexited with error [Errno 2] No such file or directory\nyarn_install is likely not on the path", "code": 1, "type": "INTERNAL_ERROR"}


Functions deploy had errors. To continue deploying other features (such as database), run:
    firebase deploy --except functions

Error: Functions did not deploy properly.
error Command failed with exit code 1.