code: function getSetting(value, key, defaultVal, transform) {
    if (process.env[key] !== undefined) {
      var envVal = process.env[key];
      return (typeof transform === 'function') ? transform(envVal) : envVal;
    }
    if (value !== undefined) {
      return value;
    }
    return defaultVal;
  }
docs: Determine an option value.
  1. If `key` is present in the environment, then use the environment value
  2. If `value` is specified, then use that value
  3. Fall back to `defaultVal`
  @module mocha-junit-reporter
  @param {Object} value - the value from the reporter options
  @param {String} key - the environment variable to check
  @param {Object} defaultVal - the fallback value
  @param {function} transform - a transformation function to be used when loading values from the environment