• Config classes.
  • UserConfig and TemplateConfig (with defaultConfig providing, um, defaults) appear to be the only classes dedicated to configuration (according to their names).
• eleventyConfig.
  • Many class constructors and methods accept an eleventyConfig argument.
  • In Eleventy.initializeConfig(), this is a TemplateConfig instance.
  • A TemplateConfig instance holds a reference to a UserConfig instance. If I understand correctly, this is so that a user’s configuration can be tweaked on a template-by-template basis. Is this correct?
• “Config” vs. “options”.
• When a class handles both “config” and “options”, what distinguishes whether a setting falls into one category or

• Modern ES code. ES/JS moves fast these days. I want Metalsmith 3 to be best-in-class, and stay best-in-class for several years.

• Performance (with Scalability). If Metalsmith 3 can boast performance that is so good, big companies with big websites start using it, that would be pretty fantastic. :)

• Convenience.

NOTE: This is a question I found on StackOverflow which I’ve archived here, because the answer is so effing phenomenal.

If you are not into long explanations, see [Paolo Bergantino’s answer][2].

This is all based on the [alpha release][1].

From the built-in help system:

For many settings, TextMate will look for a .tm_properties file in the current folder, and in any parent folders (up to the user’s home folder).

These are simple «setting» = «value» listings, where «value» is a format string in which other variables can be referenced.