gistfile1.js

function nameToCamel(name) {
  words = name.split(/[-_]/);
  for(var i = 0; i < words.length; ++i) {
    words[i] = words[i].substr(0, 1).toUpperCase() + words[i].substr(1);
  }
  return words.join('');
}

var node = document.getElementById("test");
var attrs = {};
for(var i = 0; i < node.attributes.length; ++i) {
  var attr = node.attributes[i];
  if (attr.name.match(/^data-/)) {
    attrs[nameToCamel(attr.name.substr(5))] = attr.value;
  }
}
/* TADA */
console.log(attrs);