Every time saving (building) the manifest.json file, I get an error
This error keeps showing up, even though my manifest.json file is following exactly what's on sketch's developer site:

(node:9438) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): TypeError: compilers.map is not a function

This error is non-descriptive and I'm not sure how to fix this?