decl.js

[].slice.call(document.querySelectorAll('#content > div.fixedFont'), 0).map(function(i, n){
  const text = i.innerText;
  let desc = i.nextSibling;
  while(desc && desc.className !== 'description') {
    desc = desc.nextSibling;
  }
  const m = text.match(/\{([^\}]+)\}\s(.+)$/) || ['', 'void', text];
  const retType = m[1];
  const fn = m[2];
  return '/**\n * ' + desc.innerText.replace(/\n/g, '\n * ') + '\n */\n' + fn + ': ' + retType + ';';
}).join('\n')