def start
            throw :task_has_failed unless server.start
            run_all if options[:all_on_start]
            Pry::Commands.block_command "j", "Update Jest snapshots" do | cmd |
                server = Guard.state.session.plugins.all(:jest).first.runner.server
                case cmd
                when 'u' then server.update_snapshots
                else
                    Formatter.error("unknown command #{cmd}")
                end

            end
        end
def start
            throw :task_has_failed unless server.start
            run_all if options[:all_on_start]
            Pry::Commands.block_command "j", "Update Jest snapshots" do | cmd |
                server = Guard.state.session.plugins.all(:jest).first.runner.server
                case cmd
                when 'u' then server.update_snapshots
                else
                    Formatter.error("unknown command #{cmd}")
                end

            end
        end
Initialize Guard::Jest

 @param [Hash] options the options for the Guard
 @option options [String] :config_file the location of a Jest configuration file
 @option options [String] :jest_cmd path to jest application that should be executed

 Called once when Guard starts. Please override initialize method to init stuff.

 @raise [:task_has_failed] when start has failed
 @return [Object] the task result