Encode an array of bytes into base64 and split lengthy lines in Javascript (golf code challenge)

Question

Encode an array of bytes into base64 and split lengthy lines in Javascript (golf code challenge)

This innovative JavaScript function is designed to efficiently convert an array of numbers (ranging from 0-255) into a base64-encoded string. It also includes a feature that breaks long lines, if needed:

function encode(data)
{
  var str = "";
  for (var i = 0; i < data.length; i++)
    str += String.fromCharCode(data[i]);

  return btoa(str).split(/(.{75})/).join("\n").replace(/\n+/g, "\n").trim();
}

Are you up for the challenge of achieving the same functionality with less code? Can you optimize it for faster performance? Feel free to take advantage of new language features in JavaScript for this task.

javascript firefox-addon

Answer 1

Answer №1

Here is an alternative method:

function convertToBase64(data)
{
    var str = String.fromCharCode.apply(null,data);
    return btoa(str).replace(/.{76}(?=.)/g,'$&\n');
}

When minified, it's only 88 characters long:

function c(d){return btoa(String.fromCharCode.apply(d,d)).replace(/.{76}(?=.)/g,'$&\n')}

If you prefer trailing newlines, the function can be shortened to 85 characters:

function c(d){return btoa(String.fromCharCode.apply(d,d)).replace(/.{1,76}/g,'$&\n')}

Answer 2

Here is an alternative method:

function convertToBase64(data)
{
    var str = String.fromCharCode.apply(null,data);
    return btoa(str).replace(/.{76}(?=.)/g,'$&\n');
}

When minified, it's only 88 characters long:

function c(d){return btoa(String.fromCharCode.apply(d,d)).replace(/.{76}(?=.)/g,'$&\n')}

If you prefer trailing newlines, the function can be shortened to 85 characters:

function c(d){return btoa(String.fromCharCode.apply(d,d)).replace(/.{1,76}/g,'$&\n')}

Answer 3

Answer №2

Compatible with Firefox version 3.6.13:

function convertToBase64(data)
{
    var str = data.reduce(function(a,b){ return a+String.fromCharCode(b) },'');
    return btoa(str).replace(/.{76}(?=.)/g,'$&\n');
}

Answer 4

Compatible with Firefox version 3.6.13:

function convertToBase64(data)
{
    var str = data.reduce(function(a,b){ return a+String.fromCharCode(b) },'');
    return btoa(str).replace(/.{76}(?=.)/g,'$&\n');
}

Answer 5

Answer №3

Unable to test this in Firefox right now, but looking at it from a string manipulation perspective, there seems to be room for optimization. The current method involves creating a new string one character longer than the previous one for every byte, making it an O(N^2) operation. To improve efficiency and achieve near-linear time complexity, consider the following approaches:

Build strings up to 57 characters in length (resulting in a 76-char Base64 output), then use btoa followed by adding the result to your output.
Similar to #1, create an array of lines and utilize join to form the final output.
Utilize map to generate an array of 1-character strings, followed by calling join.

Below is unverified code snippets for each approach:

function encode(data)
{
  var output = "";
  var str = "";
  for (var i = 0; i < data.length; i++)
  {
    str += String.fromCharCode(data[i]);
    if (str.length == 57 && i != data.length - 1)
    {
      output += btoa(str) + "\n";
      str = "";
    }
  }
  return output + btoa(str);
}

function encode(data)
{
  var output = [];
  var str = "";
  for (var i = 0; i < data.length; i++)
  {
    str += String.fromCharCode(data[i]);
    if (str.length == 57)
    {
      output[output.length] = btoa(str);
      str = "";
    }
  }
  if (str != "")
    output[output.length] = btoa(str);
  return output.join("\n");
}

function encode(data)
{
  var str = data.map(function (d) { return String.fromCharCode(d) }).join("");
  return btoa(str).replace(/.{76}(?=.)/g,'$&\n');
}

And here's a minified version of the last option with only 116 characters:

function e(b){return btoa(b.map(function(d){return
String.fromCharCode(d)}).join("")).replace(/.{76}(?=.)/g,'$&\n')}

Answer 6

Unable to test this in Firefox right now, but looking at it from a string manipulation perspective, there seems to be room for optimization. The current method involves creating a new string one character longer than the previous one for every byte, making it an O(N^2) operation. To improve efficiency and achieve near-linear time complexity, consider the following approaches:

Build strings up to 57 characters in length (resulting in a 76-char Base64 output), then use btoa followed by adding the result to your output.
Similar to #1, create an array of lines and utilize join to form the final output.
Utilize map to generate an array of 1-character strings, followed by calling join.

Below is unverified code snippets for each approach:

function encode(data)
{
  var output = "";
  var str = "";
  for (var i = 0; i < data.length; i++)
  {
    str += String.fromCharCode(data[i]);
    if (str.length == 57 && i != data.length - 1)
    {
      output += btoa(str) + "\n";
      str = "";
    }
  }
  return output + btoa(str);
}

function encode(data)
{
  var output = [];
  var str = "";
  for (var i = 0; i < data.length; i++)
  {
    str += String.fromCharCode(data[i]);
    if (str.length == 57)
    {
      output[output.length] = btoa(str);
      str = "";
    }
  }
  if (str != "")
    output[output.length] = btoa(str);
  return output.join("\n");
}

function encode(data)
{
  var str = data.map(function (d) { return String.fromCharCode(d) }).join("");
  return btoa(str).replace(/.{76}(?=.)/g,'$&\n');
}

And here's a minified version of the last option with only 116 characters:

function e(b){return btoa(b.map(function(d){return
String.fromCharCode(d)}).join("")).replace(/.{76}(?=.)/g,'$&\n')}

Encode an array of bytes into base64 and split lengthy lines in Javascript (golf code challenge)

Answer №1

Answer №2

Answer №3

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