Description

Caching makes styler faster on repeated styling and is shared across all APIs (e.g. style_text() and Addin). That means if you style code that already complies to a style guide and you have previously styled that code, it will be quicker.

Manage the cache

See cache_info(),cache_activate() or cache_clear() for utilities to manage the cache. You can deactivate it altogether with cache_deactivate(). Since we leverage {R.cache} to manage the cache, you can also use any {R.cache} functionality to manipulate it.

Interactive setup

{styler} by default uses caching via the {R.cache} package. When interacting with {styler}, you will be asked to let it create a permanent cache on your file system that styler will use in case it is not set already up for another tool that uses {R.cache}. We encourage users to let {R.cache} create a permanent directory for caching because, otherwise, the cache is lost at restart of R.

Non-interactive setup

In some cases, you want to avoid the interactive prompt described above. In that situation, you can set the path to the cache with the R option R.cache.rootPath or the environment variable R_CACHE_ROOTPATH to an existent path before you call the styler API. This should avoid the prompt. R.cache::setCacheRootPath("/path/to/cache") is also programmatic but will probably give the prompt anyways if called interactively.

Non-interactive use

Note that if you have never authorized {R.cache} to create the cache in a permanent directory and you use {styler} non-interactively, it will build the cache in a temporary directory. To create a permanent cache, follow the section 'Non-interactive setup' or 'Interactive setup' above.

Invalidation

The cache is specific to a version of styler by default, because different versions potentially format code differently. This means after upgrading styler or a style guide you use, the cache will be re-built.

Mechanism and size

The cache works by storing hashed output code as a whole and by expression, which is why it takes zero space on disk (the cache is a directory with empty files which have the hash of output code as name).

Using a cache for styler in CI/CD

If you want to set up caching in a CI/CD pipeline, we suggest to set the {R.cache} root path to a directory for which you have the cache enabled as described above in the section 'Non-interactive setup'. This can often be set in config files of CI/CD tools, e.g. see the Travis documentation on caching.

See Also

Other cache managers: cache_activate(), cache_clear(), cache_info()