code: function createTypings(appRoot, options){
    const filePath = path.join(appRoot,'typings.d.ts')
    const exists = fs.existsSync( filePath )
    if(exists)return
    fs.writeFileSync(filePath, typingsConfig)
    log('created',filePath)
  }
docs: /*
  function writeTsAotConfig(appRoot, options){
  const filePath = path.join(appRoot,'tsconfig.aot.json')
  const exists = fs.existsSync( filePath )
  if(exists)return
  const config = tsAotConfig
  if(options && options.createTypings){
  config.files = config.files || []
  config.files.push('typings.d.ts')
  }
  fs.writeFileSync(filePath, JSON.stringify(config, null, 2))
  log('created',filePath)
  }