Simple proof of work concept using javascript

proofOfWork.js

// Proof or work
const difficulty = 3
async function sha256(message) {
    const msgBuffer = new TextEncoder().encode(message);
    const hashBuffer = await crypto.subtle.digest('SHA-256', msgBuffer);
    const hashArray = Array.from(new Uint8Array(hashBuffer));
    const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
    return hashHex;
}

function convertBase(value, to_range) {
  const from_base = 10;
  const to_base = to_range.length;
  var from_range = "0123456789";
  
  var dec_value = value.toString().split('').reverse().reduce(function (carry, digit, index) {
    if (from_range.indexOf(digit) === -1) throw new Error('Invalid digit `'+digit+'` for base '+from_base+'.');
    return carry += from_range.indexOf(digit) * (Math.pow(from_base, index));
  }, 0);
  
  var new_value = '';
  while (dec_value > 0) {
    new_value = to_range[dec_value % to_base] + new_value;
    dec_value = (dec_value - (dec_value % to_base)) / to_base;
  }
  return new_value || '0';
}

async function bruteforce(name) {
  let salt = "";
  // Loop through all possible words until sha256(name + salt) === hash000...
  let symbols = []
  for (let i = 32; i < 127; i++) {
    symbols.push(String.fromCharCode(i))
  }
  let i = 0
  while (true) {
    salt = convertBase(i, symbols)
    add = false;
    i++;

    const test = await sha256(name + salt);
    if (test.endsWith("0".repeat(difficulty))) {
      return salt;
    }
  }
}