code: function addLineHints(name, content) {
  		var
  			i = -1,
  			lines = content.split('\n'),
  			len = lines.length,
  			out = []
  		;
  		while (++i < len) {
  			out.push(lines[i] +
  				((i % 10 === 9) ? ' //' + name + ':' + (i + 1) + '//' : ''));
  		}
  		return out.join('\n');
  	}
docs: Add JavaScript line-hint comments to every 10th line of a file.