typescript-export代码问题；别人的源码看不懂？请大佬解惑

饭-米粒

这是个箭头函数吗？()还可以指定类别！
(): ServerState => {

export const defaultState = (): ServerState => {
  return {
    klippy_retries: 0, // how many times have we attempted to reconnect to klippy.
    info: {
      failed_components: [],
      klippy_connected: false, // indicates if klippy is disconnected vs shutdown.
      klippy_state: '',
      components: [],
      registered_directories: [],
      warnings: []
    },
    system_info: null,
    config: {
      authorization: {
        enabled: true
      },
      server: {}
    },
    moonraker_stats: [],
    throttled_state: {
      bits: 0,
      flags: []
    },
    cpu_temp: null
  }
}

这两个名称分别代表什么内容？
interface ServerState

export interface ServerState {
  klippy_retries: number;
  info: ServerInfo;
  system_info: SystemInfo | null;
  config: ServerConfig;
  moonraker_stats: ServerSystemStat[];
  throttled_state: ServerThrottledState | null;
  cpu_temp: number | null;
}

kogawananari

第一个指定函数返回值类型  没有返回值要写void

第二个定义类型