Adds the loader for babel compiler to the loader configuration file.
use_loader_babel(test = "\\.(js|jsx)$", use_eslint = FALSE)Test regular expression test which files should be transformed by the loader.
Whether to also add the ESlint loader.
The use_elsint argument is useful here as loaders have
to be defined in the correct order or files might be checked after
being processed by babel.
Excludes node_modules by default.