arr2tsv.js simple TSV writer

arr2tsv.js

// Small utility function to export an array to tsv
// Inspired by https://github.com/uselesscode/ucsv/blob/master/source/core.js
define(['underscore'], function (_) {
  var separator = '\t';
  var rxIsInt = /^\d+$/;
  var rxIsFloat = /^\d*\.\d+$|^\d+\.\d*$/;
  // If a string has leading or trailing space,
  // contains the separator, double quote or a newline
  // it needs to be quoted
  var rxNeedsQuoting = new RegExp('^\s|\s$|' + separator + '|"|\n');

  var prepField = function (field) {
    if (_.isString(field)) {
      // Escape any " with double " ("")
      field = field.replace(/"/g, '""');

      // If the field starts or ends with whitespace, contains " or , or a newline or
      // is a string representing a number, quote it.
      if (rxNeedsQuoting.test(field) || rxIsInt.test(field) || rxIsFloat.test(field)) {
        field = '"' + field + '"';
      // quote empty strings
      } else if (field === "") {
        field = '""';
      }
    } else if (_.isNumber(field)) {
      field = field.toString(10);
    } else if (field === null || field === undefined) {
      field = '';
    } else {
      field = field.toString();
    }
    return field;
  };
  /**
   Converts an array into a Tabulation Separated Values string.
   Each item in the array should be an array that represents one row in the CSV.
   Nulls and undefined values are interpreted as empty fields.
   @method arr2tsv
   @param {String} a The array to convert
   @returns {String} A TSV representation of the provided array.
   @example
       var books = [
           ['JavaScript: The Good Parts', 'Crockford, Douglas', 2008],
           ['Object-Oriented JavaScript', 'Stefanov, Stoyan', 2008],
           ['Effective JavaScript', 'Herman, David', 2012]
         ];
       var tsv = arr2tsv(books);
       // tsv now contains:
       //
       // JavaScript: The Good Parts  Crockford, Douglas  2008\n
       // Object-Oriented JavaScript  Stefanov, Stoyan  2008\n
       // Effective JavaScript  Herman, David 2012\n
  */
  var arr2tsv = function(a) {
    var out = '';
    for (var i = 0; i < a.length; i += 1) {
      var row = a[i];
      for (var j = 0; j < row.length; j += 1) {
        var cur = row[j];

        cur = prepField(cur);

        out += j < row.length - 1 ? cur + separator : cur;
      }
      out += "\n";
    }
    return out;
  };

  return arr2tsv;
});