Using nodejs to compare two files, and logging the differences with more than 100 consequtive bytes

compare.js

"use strict";

const fs = require("fs");
const src = fs.readFileSync("hwram.bin");
const dst = fs.readFileSync("hwram_sho.bin");

let key;
let chain = 0;
let changes = {};

for(let i = 0; i < src.length; i++) {

        let a = src[i];
        let b = dst[i];

        if(a === b) {
                chain = 0;
                continue;
        }

        if(chain === 0) {
                let num  = i.toString(16);
                while(num.length < 6) {
                        num = "0" + num;
                }

                key = "0x" + num;
        }

        changes[key] = changes[key] || 0;
        changes[key]++;
        chain++;

}

for(let key in changes) {
        if(changes[key] > 100) {
                continue;
        }
        delete changes[key];
}

console.log(changes);