javascript - double hashing sha256 NOTworking!! + how to convert to hex? -

so i've been trying mirror double hashing using sha256 in google script, , not able replicate second hash. first 1 gets replicated correctly, must off first hash being plugged next digest.

  var teststring = "hello";    var firsthash=utilities.computedigest(utilities.digestalgorithm.sha_256, teststring);     var secondhash=utilities.computedigest(utilities.digestalgorithm.sha_256, firsthash);    app.getelementbyid('balancelabel').settext("result: "+secondhash); 

i first hash , second hash on online converter. first hash matches below expectation, , second doesn't. have tried many things try modify firsthash variable can't seem make work.

this hashes should be: hello 2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824 (first round of sha-256) 9595c9df90075148eb06860365df33584b75bff782a510c6cd4883a419833d50 (second round of sha-256)

i have been trying hard byte hash , produce hex encoded string (not base64, google script seem support out of box).

can please help?

edit: appears impossible using utitilies.computedigest because accepts string input. however, checked can implement js sha256 function in google script. how double hash using byte input of first hash?

sha256 javascript function

function sign(message){ message = message || "thisisteststring"; var signature = utilities.computedigest(                 utilities.digestalgorithm.sha_1,                 message,                 utilities.charset.us_ascii); logger.log(signature); var signaturestr = ''; (i = 0; < signature.length; i++) {    var byte = signature[i];     if (byte < 0)       byte += 256; var bytestr = byte.tostring(16); // ensure have 2 chars in our byte, pad 0 if (bytestr.length == 1) bytestr = '0'+bytestr; signaturestr += bytestr; }   logger.log(signaturestr); return signaturestr; } 

you can function converting string disired format