code: function getConverter(content) {
    var rbr = /\r\n|\r|\n/g;
    var steps = [0],
      m;
  
    rbr.lastIndex = 0;
    while ((m = rbr.exec(content))) {
      steps.push(m.index + m[0].length);
    }
  
    return function(line, column) {
      if (steps.length < line) {
        return -1;
      }
  
      return steps[line - 1] + column;
    };
  }
docs: 生成转换坐标为位置的函数。