OctopusComparison quick scraping script

grab-prices-from-octopus-comparison.js

// Grabs prices from https://octopuscomparison.netlify.app/ and totals them up
// Simply paste this into the javascript console
// Relies on some hacks to trigger React onchange events

let allPrices = [];

(function() {
  function setNativeValue(element, value) {
    const valueSetter = Object.getOwnPropertyDescriptor(element, 'value').set;
    const prototype = Object.getPrototypeOf(element);
    const prototypeValueSetter = Object.getOwnPropertyDescriptor(prototype, 'value').set;
    
    if (valueSetter && valueSetter !== prototypeValueSetter) {
      prototypeValueSetter.call(element, value);
    } else {
      valueSetter.call(element, value);
    }
  }

  allPrices = [];

  const input = document.querySelector('[type="date"]')
  const start = input.min
  const end = input.max

  let loop = new Date(start);
  loop = new Date(loop.setDate(loop.getDate() + 1)); // skip first day

  let endDate = new Date(end);
  while(loop <= endDate){
    setNativeValue(input, loop.toISOString().substr(0, 10))
    input.dispatchEvent(new Event('input', { bubbles: true }));

    const prices = document.querySelector("#root > div > div > div.prices > h1").textContent
    const [ _agileName, agilePrice, _goName, goPrice ] = prices.split(/\||\:/).map((entry) => entry.trim().replace('£', ''))

    allPrices.push({date: loop.toISOString().substr(0, 10), agilePrice, goPrice})

    const newDate = loop.setDate(loop.getDate() + 1);
    loop = new Date(newDate);
  }

  const totals = allPrices.reduce((accumulator, day) => {
    accumulator.totalAgile += parseFloat(day.agilePrice)
    accumulator.totalGo += parseFloat(day.goPrice)
    accumulator.totalDifference += (parseFloat(day.goPrice) - parseFloat(day.agilePrice))

    return accumulator
  }, { totalAgile: 0, totalGo: 0, totalDifference: 0 })


  const h1 = document.querySelector("#root > div > div > div.header > h1")
  h1.textContent = `Total for ${allPrices.length} days on Agile: £${totals.totalAgile.toFixed(2)}, Go: £${totals.totalGo.toFixed(2)}, Difference: £${totals.totalDifference.toFixed(2)}`

  return totals 
})()