csvjson.js

/**
 * csvjson.js - A script to convert between CSV and JSON formats
 * Author: Aaron Snoswell (@aaronsnoswell, elucidatedbianry.com)
 */

// Namespace
csvjson = {};

// Hide from global scope
(function(){
  function isdef(ob) {
    if(typeof(ob) == "undefined") return false;
    return true;
  }

  /**
   * splitCSV function (c) 2009 Brian Huisman, see http://www.greywyvern.com/?post=258
   * Works by spliting on seperators first, then patching together quoted values
   */
  function splitCSV(str, sep) {
    for (var foo = str.split(sep = sep || ","), x = foo.length - 1, tl; x >= 0; x--) {
      if (foo[x].replace(/"\s+$/, '"').charAt(foo[x].length - 1) == '"') {
        if ((tl = foo[x].replace(/^\s+"/, '"')).length > 1 && tl.charAt(0) == '"') {
          foo[x] = foo[x].replace(/^\s*"|"\s*$/g, '').replace(/""/g, '"');
        } else if (x) {
          foo.splice(x - 1, 2, [foo[x - 1], foo[x]].join(sep));
        } else foo = foo.shift().split(sep).concat(foo);
      } else foo[x].replace(/""/g, '"');
    } return foo;
  };


  /**
   * Converts from CSV formatted data (as a string) to JSON returning
   * 	an object.
   * @required csvdata {string} The CSV data, formatted as a string.
   * @param args.delim {string} The delimiter used to seperate CSV
   * 	items. Defauts to ','.
   * @param args.textdelim {string} The delimiter used to wrap text in
   * 	the CSV data. Defaults to nothing (an empty string).
   */
  csvjson.csv2json = function(csvdata, args) {
    args = args || {};
    var delim = isdef(args.delim) ? args.delim : ",";
    // Unused
    //var textdelim = isdef(args.textdelim) ? args.textdelim : "";

    var csvlines = csvdata.split("\n");
    var csvheaders = splitCSV(csvlines[0], delim);
    var csvrows = csvlines.slice(1, csvlines.length);

    var ret = {};
    ret.headers = csvheaders;
    ret.rows = [];

    for(var r in csvrows) {
      if (csvrows.hasOwnProperty(r)) {
        var row = csvrows[r];
        var rowitems = splitCSV(row, delim);

        // Break if we're at the end of the file
        if(row.length == 0) break;

        var rowob = {};
        for(var i in rowitems) {
          if (rowitems.hasOwnProperty(i)) {
            var item = rowitems[i];

            // Try to (intelligently) cast the item to a number, if applicable
            if(!isNaN(item*1)) {
              item = item*1;
            }

            rowob[csvheaders[i]] = item;
          }
        }

        ret.rows.push(rowob);
      }
    }

    return ret;
  }	// end csv2json

  /**
   * Taken an object of the form
   * {
	 *     headers: ["Heading 1", "Header 2", ...]
	 *     rows: [
	 *	       {"Heading 1": SomeValue, "Heading 2": SomeOtherValue},
	 *	       {"Heading 1": SomeValue, "Heading 2": SomeOtherValue},
	 *         ...
	 *     ]
	 * }
   * and returns a CSV representation as a string.
   * @requires jsondata {object} The JSON object to parse.
   * @param args.delim {string} The delimiter used to seperate CSV
   * 	items. Defauts to ','.
   * @param args.textdelim {string} The delimiter used to wrap text in
   * 	the CSV data. Defaults to nothing (an empty string).
   */
  csvjson.json2csv = function(jsondata, args) {
    args = args || {};
    var delim = isdef(args.delim) ? args.delim : ",";
    var textdelim = isdef(args.textdelim) ? args.textdelim : "";

    if(typeof(jsondata) == "string") {
      // JSON text parsing is not implemented (yet)
      return null;
    }

    var ret = "";

    // Add the headers
    for(var h in jsondata.headers) {
      if (jsondata.headers.hasOwnProperty(h)) {
        var heading = jsondata.headers[h];
        ret += textdelim + heading + textdelim +  delim;
      }
    }

    // Remove trailing delimiter
    ret = ret.slice(0, ret.length-1);
    ret += "\n";

    // Add the items
    for(var r in jsondata.rows) {
      if (jsondata.rows.hasOwnProperty(r)) {
        var row = jsondata.rows[r];

        // Only add elements that are mentioned in the headers (in order, obviously)
        for(var h in jsondata.headers) {
          if (jsondata.headers.hasOwnProperty(h)) {
            var heading = jsondata.headers[h];
            var data = row[heading];

            if(typeof(data) == "string") {
              ret += textdelim + row[heading] + textdelim +  delim;
            } else {
              ret += row[heading] + delim;
            }
          }
        }

        // Remove trailing delimiter
        ret = ret.slice(0, ret.length-1);
        ret += "\n";
      }
    }

    // Remove trailing newling
    ret = ret.slice(0, ret.length-1);

    return ret;
  }

})();	// Execute hidden-scope code