Run yarn cache clean.
Run yarn help cache in your bash, and you will see:
Usage: yarn cache [ls|clean] [flags]
Options: -h, --help output usage information -V, --version output the version number --offline
--prefer-offline
--strict-semver
--json
--global-folder [path]
--modules-folder [path] rather than installing modules into the node_modules folder relative to the cwd, output them here
--packages-root [path] rather than storing modules into a global packages root, store them here
--mutex [type][:specifier] use a mutex to ensure only one yarn instance is executingVisit http://yarnpkg.com/en/docs/cli/cache for documentation about this command.