lib/line-column.js
function buildLineToIndex(str) {
  var lines = str.split("\n"),
      lineToIndex = new Array(lines.length),
      index = 0;

  for (var i = 0, l = lines.length; i < l; i++) {
    lineToIndex[i] = index;
    index += lines[i].length + /* "\n".length */ 1;
  }
  return lineToIndex;
}
function buildLineToIndex(str) {
  var lines = str.split("\n"),
      lineToIndex = new Array(lines.length),
      index = 0;

  for (var i = 0, l = lines.length; i < l; i++) {
    lineToIndex[i] = index;
    index += lines[i].length + /* "\n".length */ 1;
  }
  return lineToIndex;
}
function buildLineToIndex ( str ) { var lines = str . split ( "\n" ) , lineToIndex = new Array ( lines . length ) , index = 0 ; for ( var i = 0 , l = lines . length ; i < l ; i ++ ) { lineToIndex [ i ] = index ; index += lines [ i ] . length + /* "\n".length */ 1 ; } return lineToIndex ; }
Build an array of indexes of each line from a string.

@private
@param   str {string}  An input string.
@return  {number[]}    Built array of indexes. The key is line number.
Build an array of indexes of each line from a string .