JavaScript - Make SHA256 hash from another JS script result

Question

I need help with creating JS script for making SHA256 hash from another JS script result. I need to make SHA256 hash from result of this script;

function test(length) {
    let result = '';
    const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
    const charactersLength = characters.length;
    let counter = 0;
    while (counter < length) {
      result += characters.charAt(Math.floor(Math.random() * charactersLength));
      counter += 1;
    }
    return result;
}
console.log(test(16));

Someone with decent knowledge in basic cryptography and JS, reply this question.

I tried doing it by copying this script from another Stack Overflow user;

var makeserverseed = function sha256(ascii) {
  function rightRotate(value, amount) {
      return (value>>>amount) | (value<<(32 - amount));
  };
  
  var mathPow = Math.pow;
  var maxWord = mathPow(2, 32);
  var lengthProperty = 'length'
  var i, j;
  var result = ''

  var words = [];
  var asciiBitLength = ascii[lengthProperty]*8;
  
  var hash = sha256.h = sha256.h || [];
  var k = sha256.k = sha256.k || [];
  var primeCounter = k[lengthProperty];

  var isComposite = {};
  for (var candidate = 2; primeCounter < 64; candidate++) {
      if (!isComposite[candidate]) {
          for (i = 0; i < 313; i += candidate) {
              isComposite[i] = candidate;
          }
          hash[primeCounter] = (mathPow(candidate, .5)*maxWord)|0;
          k[primeCounter++] = (mathPow(candidate, 1/3)*maxWord)|0;
      }
  }
  
  ascii += '\x80'
  while (ascii[lengthProperty]%64 - 56) ascii += '\x00' 
  for (i = 0; i < ascii[lengthProperty]; i++) {
      j = ascii.charCodeAt(i);
      if (j>>8) return; 
      words[i>>2] |= j << ((3 - i)%4)*8;
  }
  words[words[lengthProperty]] = ((asciiBitLength/maxWord)|0);
  words[words[lengthProperty]] = (asciiBitLength)
  
  for (j = 0; j < words[lengthProperty];) {
      var w = words.slice(j, j += 16); 
      var oldHash = hash;
      hash = hash.slice(0, 8);
      
      for (i = 0; i < 64; i++) {
          var i2 = i + j;
          var w15 = w[i - 15], w2 = w[i - 2];
          var a = hash[0], e = hash[4];
          var temp1 = hash[7]
              + (rightRotate(e, 6) ^ rightRotate(e, 11) ^ rightRotate(e, 25)) // S1
              + ((e&hash[5])^((~e)&hash[6])) // ch
              + k[i]
              + (w[i] = (i < 16) ? w[i] : (
                      w[i - 16]
                      + (rightRotate(w15, 7) ^ rightRotate(w15, 18) ^ (w15>>>3)) // s0
                      + w[i - 7]
                      + (rightRotate(w2, 17) ^ rightRotate(w2, 19) ^ (w2>>>10)) // s1
                  )|0
              );
          var temp2 = (rightRotate(a, 2) ^ rightRotate(a, 13) ^ rightRotate(a, 22)) // S0
              + ((a&hash[1])^(a&hash[2])^(hash[1]&hash[2])); // maj
          
          hash = [(temp1 + temp2)|0].concat(hash);
          hash[4] = (hash[4] + temp1)|0;
      }
      
      for (i = 0; i < 8; i++) {
          hash[i] = (hash[i] + oldHash[i])|0;
      }
  }
  
  for (i = 0; i < 8; i++) {
      for (j = 3; j + 1; j--) {
          var b = (hash[i]>>(j*8))&255;
          result += ((b < 16) ? 0 : '') + b.toString(16);
      }
  }
  return result;
};
console.log(makeserverseed);

For example let's say that my random string from 1st script is 'SLvZAfpv2zEPYg5F', I need to make SHA256 hash for it in JavaScript and console log it. The hash for SHA256 of 'SLvZAfpv2zEPYg5F' is: "2ab51f5928246656e753f6518dea0e0745c8faf9429578136c13181bb36d926b" and I need to find a way to display it in my console. Thanks in advance!

Answer 1

If you are in a secure context then this should work:

function sha256(input) {
  const buffer = new TextEncoder().encode(input);
  return ( 
    crypto.subtle.digest('SHA-256', buffer)
    .then(hashBuffer => {
      const hashArray = Array.from(new Uint8Array(hashBuffer));
      const hashHex = hashArray.map(byte => byte.toString(16).padStart(2, '0')).join('');
      return hashHex;
    })
  );
}
 
// And to use

const textToHash = 'want to hash this string';

sha256(textToHash)
  .then(hashed => {
    console.log('hashed', hashed);
    // do stuff here
  })
  .catch(console.log);

The docs MDN SubtleCrypto