JavaScript native ASCII to Binary / Binary to ASCII convert functions.

ascii-binary-converter.js

// ABC - a generic, native JS (A)scii(B)inary(C)onverter.
// (c) 2013 Stephan Schmitz <[email protected]>
// License: MIT, http://eyecatchup.mit-license.org
// Original URL: https://gist.github.com/eyecatchup/6742657
//
// Slightly modified by Darrin W. Cullop ([email protected])
// URL: https://gist.github.com/dwcullop/590d84b51a13e0cdda74
var ABC = {
  toAscii: function(bin) {
    return bin.match(/[01]{8}/g)
              .map( function(b) { return String.fromCharCode(parseInt(b,2)); } )
              .join("");
  },
  toBinary: function(str, spaceSeparatedOctets) {
    return str.match(/[\s\S]/g)
              .map(function(s) { return ABC.zeroPad(s.charCodeAt().toString(2)); } )
	            .join( (+spaceSeparatedOctets != 0) ? " " : "" );
  },
  zeroPad: function(num) {
    return ("00000000" + num).substr(-8);
  }
};

ascii-binary-converter.min.js

// ABC - a generic, native JS (A)scii(B)inary(C)onverter.
// (c) 2013 Stephan Schmitz <[email protected]>
// License: MIT, http://eyecatchup.mit-license.org
// Original URL: https://gist.github.com/eyecatchup/6742657
//
// Slightly modified by Darrin W. Cullop ([email protected])
// URL: https://gist.github.com/dwcullop/590d84b51a13e0cdda74
var ABC={toAscii:function(n){return n.match(/[01]{8}/g).map(function(n){return String.fromCharCode(parseInt(n,2))}).join("")},toBinary:function(n,r){return n.match(/[\s\S]/g).map(function(n){return ABC.zeroPad(n.charCodeAt().toString(2))}).join(0!=+r?" ":"")},zeroPad:function(n){return("00000000"+n).substr(-8);}};

test-abc.js

var binary1      = "01100110011001010110010101101100011010010110111001100111001000000110110001110101011000110110101101111001",
    binary2      = "01100110 01100101 01100101 01101100 01101001 01101110 01100111 00100000 01101100 01110101 01100011 01101011 01111001",
    binary3      = "01010100 01101000 01100101 01110010 01100101 00100000 01100001 01110010 01100101 00100000 00110001 00110000 00100000 01101011 01101001 01101110 01100100 01110011 00100000 01101111 01100110 00100000 01110000 01100101 01101111 01110000 01101100 01100101 00101110 00100000 01010100 01101000 01101111 01110011 01100101 00100000 01110111 01101000 01101111 00100000 01101011 01101110 01101111 01110111 00100000 01100010 01101001 01101110 01100001 01110010 01111001 00100000 01100001 01101110 01100100 00100000 01110100 01101000 01101111 01110011 01100101 00100000 01110111 01101000 01101111 00100000 01100100 01101111 01101110 00100111 01110100 00101110",
    binary1Ascii = ABC.toAscii(binary1),
    binary2Ascii = ABC.toAscii(binary2),
    binary3Ascii = ABC.toAscii(binary3);

console.log("Binary 1:                   " + binary1);
console.log("Binary 1 to ASCII:          " + binary1Ascii);
console.log("Binary 2:                   " + binary2);
console.log("Binary 2 to ASCII:          " + binary2Ascii);
console.log("Binary 3:                   " + binary3);
console.log("Binary 3 to ASCII:          " + binary3Ascii);
console.log("Ascii to Binary:            " + ABC.toBinary(binary1Ascii));     // default: space-separated octets
console.log("Ascii to Binary /wo spaces: " + ABC.toBinary(binary1Ascii, 0));  // 2nd parameter false to not space-separate octets
console.log("Does it work:               " + (binary3 == ABC.toBinary(binary3Ascii)) );

While the original worked great, I just had a couple of minor tweaks. Probably more of personal preference than performance tweaks, but I stand by them. I also (slightly) expanded the unit test suite. Excellent work on the original. Very succinct and efficient.