Javascript: How to convert dec byte array object into hex string?

Question

So i have an object, type "Buffer", data is array of [0,0,2,6,116].

If treat this array as decimals, i want to convert into hex string. 0, 0, 2, 6, 116 => 0, 0, 2, 6, 74 => 00, 00, 02, 06, 74

Eventually i want to see 20674 or 0000020674 in the webpage.

What's the fastest way/build-in function in Javascript please ?

Answer 1

String concatenation might be expensive depending of the size of your buffer. So the quickest way is probably to encode the data and use String.fromCharCode to build the string :

function dataToString(data){
  var buffer = [], table = [48,49,50,51,52,53,54,55,56,57,65,66,67,68,69,70];

  for (var i = 0; i < data.length; ++i){
    buffer.push(table[data[i] >> 4]); 
    buffer.push(table[data[i] & 15]);
  }

  return String.fromCharCode.apply(String, buffer);
}

dataToString([0,0,2,6,116]);

Or with string concatenation:

[0,0,2,6,116].map(v => "0123456789ABCDEF"[v >> 4] + "0123456789ABCDEF"[v & 15]).join('');