A code sample from the article http://joshwulf.com/blog/2020/02/functional-refactor

deploy-refactor-final.ts

public async deployWorkflow(
  workflow: ZB.DeployWorkflowFiles | ZB.DeployWorkflowBuffer
): Promise<ZB.DeployWorkflowResponse> {
  
  const deploy = (workflows: ZB.WorkflowRequestObject[]) =>
    this.executeOperation('deployWorkflow', () =>
      this.gRPCClient.deployWorkflowSync({
        workflows,
      })
    )

  const error = (e: NEA.NonEmptyArray<string>) =>
    Promise.reject(
      `Deployment failed. The following files were not found: ${e.join(
        ', '
      )}.`
    )
  
  return pipe(
    bufferOrFiles(workflow),
    E.fold(deploy, files =>
      pipe(
        mapThese(files, readDefinitionFromFile),
        E.fold(error, deploy)
      )
    )
  )
}