Parsing

from

from is a utility to parse a primitive value (string or number) into a enumerated value.

from is safely typed. If the given primitive value was not able to be parsed, from will return undefined. Otherwise, a default value could be given to from to handle such case.

enum _LogLevel {
  Info = 'INFO',
  Warn = 'WARN',
  Error = 'ERROR',
}
class LogLevel extends extend<typeof _LogLevel, _LogLevel>(_LogLevel) {}

// USAGE
const level0 = LogLevel.from('INFO');                // LogLevel.Info
const level1 = LogLevel.from('FOO');                 // undefined
const level2 = LogLevel.from('FOO', LogLevel.Error); // LogLevel.Error