next-chain

invoke next callback function and form a execution chain

Motivation

passing next as callback as a mean of flow control is very usefule pattern used by many libraries, such as koa. It looks like:

app.use(function loginRequired (ctx, next) {
    if (notAuthenticated) {
        // next will not be executed if not authenticated
        ctx.body = 'login required'
        return
    }
    await next()
})

And I made this library to implement this pattern

Installation

$ npm i next-chain

Usage

esm way

import nextChain from 'next-chain'

commonjs way

const nextChain = require('next-chain')

Example

nextChain({ foo: 1 })(
  (o, next) => {
    // if o.foo is odd, invoke next, otherwise stops here
    if (o.foo & 1) {
      next()
    }
  },
  o => ++o.foo
).then(it => console.log(it.foo)) // 2

check test.js for more details

API

nextChain(...args)

parameters

• args - arguments passed to next callbacks

return

a function that accepts an array of functions, which will use args plus a next callback as arguments, this function will execute these functions and return a promise

Development

$ git clone https://github.com/xiechao06/next-chain.git
$ cd next-chain
$ npm ci
$ npm run build
$ npm run test