function when(condition, configSetters) {
  assertConfigSetters(configSetters)

  if (condition) {
    return group(configSetters)
  } else {
    return () => config => config
  }
}
Applies an array of webpack blocks only if `condition` is true.

@param {boolean} condition         Condition to test
@param {Function[]} configSetters  Array of functions as returned by webpack blocks.
@return {Function}