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 |