Allow specifying extensions

[TehShrike]

Right now envify processes files of all extensions, except for .json.

I'm in a situation where I'm requiring files of different extensions (.html to load template strings, .tag for RiotJS tag files), and I need envify to apply only to .js, and ignore those files.

I think this could be added in a pretty-backwards-compatible way:

If the env property is not an object, the current behavior is assumed:

envify({
  _: 'purge',
  BUTTS: 'YES',
  env: 'PRODUCTION'
})

If the env property is an object, its properties are used as the environment variables, and the rest of the top-level object is used for options like purge and extensions:

envify({
  purge: true,
  extensions: ['.js', '.mjs'],
  env: {
    BUTTS: 'YES',
    env: 'PRODUCTION'
  }
})

What do you think? Would you take a pull request implementing this change? Would you prefer a different implementation, or would you rather not support different extensions?

[yoshuawuyts]

Hey there, thanks for opening this issue!

would you rather not support different extensions

I know Hugh's stance is to not extend the scope of this package further, and I'm pretty "meh" about applying certain variables only to certain files: so no thank you!