@gemini/configparser

Parser for testplane configuration files.

Config is described with a combination of a functions:

``js
var parser = root(section({
system: section({
parallelLimit: option({
parseEnv: Number,
parseCli: Number,
validate: function() {...}
})
}),
browsers: map(
section({
calibrate: option(...),
windowSize: option(...)
})
)
})
`

There are 4 types of values:

* option({defaultValue, parseCli, parseEnv, validate, map}) - a single scalar option.
- defaultValue - a default value to use if option is not provided
- defaultValue(config, currentNode) - a function to compute default value
- parseCli(value) - a function used to parse command-line arguments
- parseEnv(value) - a function used to parse environment variable
- validate(value, config, currentNode, meta) - a function used to validate the option value
- map(value, config, currentNode, meta) - a function used to transform the option value
* section({sectionName1: valueParser1, sectionName2: valueParser2, ...}) - a section of a
values with specified key names. Each option will parsed with appropriate parser function.
Any unknown value passed by user will be treated as an error.
* map(valueParser, defaultValue) - a map with any number of user-specified keys. Each value is parsed by
valueParser. If set, defaultValue will be used in case of no user-specified data provided.
* root(parser, {envPrefix, cliPrefix}) - creates a root config parsers from specifed parser function. Returns function with signature f({options, env, argv})`.