Get Bun stats sorted diff

get-stats-diff.js

import fs from 'node:fs/promises';

const before = await readJson('./stats_before.json');
const after = await readJson('./stats_after.json');

getDiff(before, after)
  .sort((a, b) => b[1] - a[1])
  .forEach(([key, value]) => {
    console.log(key, `+${value}`);
  });

function getDiff(a, b, prefix = '') {
  const result = [];
  for (const key of Object.keys(a)) {
    const beforeVal = a[key];
    const afterVal = b[key];

    if (typeof beforeVal === 'number') {
      if (afterVal - beforeVal > 0) {
        result.push([`${prefix}${key}`.padEnd(48, ' '), afterVal - beforeVal]);
      }
    }

    if (beforeVal !== null && typeof beforeVal === 'object') {
      result.push(...getDiff(beforeVal, afterVal, `${key}.`));
    }
  }

  return result;
}

function readJson(filename) {
  return fs.readFile(filename, 'utf-8').then(JSON.parse);
}