CSV Parser in Javascript

lib.csv.js

/* CSV parser 
 * (c) Sam Briesemeister, 2012
 *
 * Features:
 *  - Parses CSV through a sequential tokenizer
 *  - Supports alternative field separator and quote characters
 *  - Ignores empty lines and comments (lines starting with #)
 *  - Provides label support through lookup function
 *
 * Usage:
 * 
 *  // sample string
 *  var mycsv = "one,two\nthree,four\nfive,six";
 *  
 *  // simple parser with defaults
 *  window.CSV(mycsv)[1][1] == 'four';
 *
 *  // standard CSV tokens (defaults, but explicitly given)
 *  window.CSV(mycsv, ",", "\"")
 *
 *  // CSV parser with labels (ignores first line)
 *  window.CSV(mycsv, null, null, true).get('one', 1) == 'five';
 * 
 *
 *  // TSV with single-quote format
 *  window.CSV(otherstring, "\t", "'")
 *
 */

(function(win, doc){ 

  // in-memory cache for regular expressions (tokenizers)
  var token_cache = {};
  
  // retrieve a tokenizer from cache if available, or create/store it.
  function get_tokenizer(sep, quot){
    var n = sep + quot;
    return (token_cache[n] = token_cache[n] || new RegExp('(' + quot + '((?:\\\\' + quot + '|(?:\\r?\\n)*|[^' + quot + '])*)' + quot + '|' + sep + '|(\\r?\\n)|([^' + sep + '\\r\\n]*))', 'g'));
  }


  function add_methods(lbl, rows){

    // prepare label map if needed
    var map = lbl ? {} : null, i = lbl && lbl.length;
    if(i) while(i--) map[ lbl[i] ] = i;

    rows['get'] = function(name, row){
      var valid_row = (rows.length > row);
      if(map && valid_row && name in map && map.hasOwnProperty(name)){
        return rows[row][map[name]];
      } else if(valid_row && name === Number(name)){
        return rows[row][name];
      }
    };

    return rows;
  }
  
  // process a CSV string 
  function parse_data(string, sep, quot, lbl){
    
    var tokenizer = get_tokenizer(sep, quot);
    
    // record state
    var rows = [ ], cur = 0, last_nl = false;
    
    // loop over the string by tokenizer
    string.replace(tokenizer, function($0, tok, quoted, nl, rest){
      rows[cur] = rows[cur] || []; // ensure a current record exists
      // order matters here?
      if(quoted){
        // add a quoted field (possibly including newlines, etc) to the current record
        last_nl = false;
        return rows[cur].push(quoted);
      } else if(nl){
        // found new line, queue next record
        last_nl = true;
        return cur++;
      } else if(rest){
        // add whatever else we found (an unquoted field) to the current record
        last_nl = false;
        return rows[cur].push(rest);
      } else if(tok == '#' && !last_nl){
        
      }
    });

    if(lbl){
      rows = add_methods(rows['labels'] = rows.shift(), rows);
    } else {
      rows = add_methods(null, rows);
    }
  
    return rows;
  }

  // Remove comment lines (starting with #) and empty lines
  var blanklines = /(\r?\n)+/g, commentlines = /(?:^|\r?\n)#([^\n]*)(\r?\n)/g;
  function clean_csv(str){
    return str.replace(commentlines, '$2').replace(blanklines, '\n');
  }

  // export shortcut with sane defaults
  var _export = win['CSV'] = function(string, sep, quote, labels){
    var sep = sep || ',', quote = quote || '"';
    return parse_data(clean_csv(string), sep, quote, labels);
  };


})(window, document);

lib.csv.min.js

(function(){
function h(a,b){var c=a?{}:null,f=a&&a.length;if(f)for(;f--;)c[a[f]]=f;b.get=function(e,d){var a=b.length>d;if(c&&a&&e in c&&c.hasOwnProperty(e))return b[d][c[e]];if(a&&e===Number(e))return b[d][e]};return b}var i={},j=/(\r?\n)+/g,k=/(?:^|\r?\n)#([^\n]*)(\r?\n)/g;
window.CSV=function(a,b,c,f){var b=b||",",c=c||'"',a=a.replace(k,"$2").replace(j,"\n"),e=b+c,b=i[e]=i[e]||RegExp("("+c+"((?:\\\\"+c+"|(?:\\r?\\n)*|[^"+c+"])*)"+c+"|"+b+"|(\\r?\\n)|([^"+b+"\\r\\n]*))","g"),d=[],g=0;a.replace(b,function(b,c,a,e,f){d[g]=d[g]||[];if(a)return d[g].push(a);if(e)return g++;if(f)return d[g].push(f)});return d=f?h(d.labels=d.shift(),d):h(null,d)};
}());