Get total image size from HAR file

foo.js

const fs = require('fs');

const harPath = `${__dirname}/my-site.har`;
const harString = fs.readFileSync(harPath, 'utf-8');
const harParsed = JSON.parse(harString);

const { entries } = harParsed.log;

const isImageEntry = entry => entry.request.url.startsWith('https://images.unsplash.com/photo-');

const sizes = entries
  .filter(isImageEntry)
  .map(entry => entry.response.content.size);

const add = (a, b) => a + b;
const totalSize = sizes.reduce(add, 0);

console.log(totalSize / 1024);