sabar

A tiny middleware combiner has back, next, abort and resume actions

Motivation

A action could split into minor action, and every minor action has a connection. such as trigger next one if success, retry from last step, or restart from beginning..

For this purpose, every minor task should comply with a semantically pattern. In sabar, the last two params will be ctx and actions

Install

npm i sabar

Simple example

import Sabar from 'sabar'

const payment = new Sabar()

const validateIdentity = (user, ctx, actions) => {
  const falsy = validate(use.identity)
  if (falsy) actions.next()
  else actions.resume()
}

const validateAccount = (user, ctx, actions) => {
  const falsy = isAfford(use.account)
  if (falsy) actions.next()
  else action.resume()
}

payment.use(validateIdentity)
payment.use(validateAccount)

const user = {
  identify: { name: 'charlie' },
  account: 100,
}
payment.start(user)

Usage

Sabar({ ctx: object, onError?: Function, onSuccess?: Function, onFinish?: Function })

Property	Description	Type	Required
ctx	Initial value of ctx and default as {}. It will be shared between middleware	object	no
onError	Triggered when abort function is invoked	Function	no
onSuccess	Triggered when there is no nextSibling of current running middleware	Function	no
onFinish	Trigger when onError or onSuccess is invoked	Function	no

Provide initial ctx value

const payment = new Sabar({ ctx: { paymentMethod: 'visa' }})

use(...args: Sabar | <...T>(...args: [...T, ctx, actions])[] => void)

use is to register fn to sabar instance. fn is an variadic function with ctx and actions tailing params.

const payment = new Sabar({ ctx: { paymentMethod: 'visa' }})

const validateAddress = (args, ctx, actions) => {
  const { location, name } = args
  if (!isValidAddress({ location, name })) {
    return actions.abort()
  }

  actions.next()
}

const validateCard = (args, ctx, actions) => {
  const { cardNumber } = args
  if (!isValidCard({ cardNumber })) {
    return actions.abort()
  }

  actions.next()
}

const applyPayment = payment.use(
  validateAddress,
  validateCard,
)

arg could be a Sabar object. In this condition, Sabar will copy middleware from arg object.

const job = new Sabar()
job.use(fn)

const nextJob = new Sabar()
nextJob.use(job)

job.start()
nextJob.start()

start(...args: array[])

start will make actions begin running. It args will be passing between middleware as heading params.

const job = new Sabar()
job.use(fn)

job.start()

actions

Property	Description
next	Trigger next middleware
back	Rerun from last middleware
abort	Stop middleware running
resume	Rerun from beginning