Node.Child_processNode Child Process API
let option: ?cwd:string => ?encoding:string => unit => option;let execSync: string => option => string;let spawnSync: string => spawnResult;let readAs: 
  spawnResult =>
  Js.t({. pid: int
    , status: Js.null(int)
    , signal: Js.null(string)
    , stdout: Js.null(Node.string_buffer)
    , stderr: Js.null(Node.string_buffer)});