code: function injectHook(options, name, hook) {
    const existing = options[name]
    options[name] = existing
      ? Array.isArray(existing) ? existing.concat(hook) : [existing, hook]
      : [hook]
  }
docs: Inject a hook to a hot reloadable component so that
  we can keep track of it.
  
  @param {Object} options
  @param {String} name
  @param {Function} hook