async-wrap

Library with wrapper functions for async function (or functions, that return Promises)

Install

npm install async-wrap

Usage

var asw = require('async-wrap')
 
asw.coalesce([1,2,3],asyncfun)

or

var coalesce = require('async-wrap/coalesce')
 
coalesce([1,2,3],asyncfun)

Overview

• coalesce

Functions

coalesce

Accepts two parameters:

• elements {Array}: List of elements that should be passed to the callback
• callback {function}: Async callback function (promise) that accepts an element as parameter

Use coalesce to execute a async function again, when it fails, with the next element in the elements list. E.g. you have multiple instances of a service, and want to retry the request with the next service instance if you can't connect to the first service.

Example:

Interactive example on runkit

function getItems(){
    var urls = getServiceUrls() // Returns array
    return coalesce(urls, requestItems)
 
    async function requestItems(url) {
        return asyncRequest(url+'/api/items')
    }
}

Same using Promise:

function getItems(){
    var urls = getServiceUrls() // Returns array
    return coalesce(urls, requestItems)
 
    function requestItems(url) {
        return new Promise((resolve, reject) => {
            request(url+'/api/items',(error, body) => {
                if (error) reject(error)
                else resolve(body)
            })
        })
 
    }
}

With multiple parameters:

function getItemInfo(id){
    var urls = getServiceUrls() // Returns array
    return coalesce(urls, (url) => requestItemInfo(url,id))
 
    async function requestItemInfo(url, id) {
        return asyncRequest(url+'/api/item/'+id)
    }
}