Get the average price of a search on ebay

ebay-average-price.js

/************************************************
* Utils
************************************************/

const injectScript = url => 
  document.body.appendChild(document.createElement('script')).src = url
 
const querySelectorAllArray = selector => 
  [...document.querySelectorAll(selector)]
  
const execWhenReady = fn =>
  ["complete", "interactive"].includes(document.readyState)
    ? fn()
    : addEventListener("load", fn)

/************************************************
* Main
************************************************/

const scripts = [
  '//cdn.jsdelivr.net/npm/ramda@0.25/dist/ramda.min.js',
  '//cdnjs.cloudflare.com/ajax/libs/ramda-adjunct/2.28.0/RA.web.min.js'
]

const main = () => {
  const nodesToFloats = R.pipe(
    R.map(x => x.innerText),
    R.map(R.slice(1, Infinity)),
    R.map(parseFloat),
    R.filter(RA.isFloat)
  )
  
  R.pipe(
    querySelectorAllArray,
    nodesToFloats,
    R.mean,
    RA.round,
    alert
  )('.s-item__price .POSITIVE')
}

scripts.map(injectScript)
execWhenReady(main)