code: function addLineNumbers(src, lineOffset) {
    lineOffset = lineOffset || 0;
    ++lineOffset;
  
    return src.split("\n").map(function(line, ndx) {
      return (ndx + lineOffset) + ": " + line;
    }).join("\n");
  }
docs: eslint-disable-line 
  Error Callback
  @callback ErrorCallback
  @param {string} msg error message.
  @param {number} [lineOffset] amount to add to line number
  @memberOf module:twgl