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backend.csv.js

this.recline = this.recline || {};
this.recline.Backend = this.recline.Backend || {};
this.recline.Backend.CSV = this.recline.Backend.CSV || {};

Note that provision of jQuery is optional (it is only needed if you use fetch on a remote file)

(function(my) {
  my.__type__ = 'csv';

use either jQuery or Underscore Deferred depending on what is available

  var Deferred = _.isUndefined(this.jQuery) ? _.Deferred : jQuery.Deferred;

fetch

fetch supports 3 options depending on the attribute provided on the dataset argument

  1. dataset.file: file is an HTML5 file object. This is opened and parsed with the CSV parser.
  2. dataset.data: data is a string in CSV format. This is passed directly to the CSV parser
  3. dataset.url: a url to an online CSV file that is ajax accessible (note this usually requires either local or on a server that is CORS enabled). The file is then loaded using jQuery.ajax and parsed using the CSV parser (NB: this requires jQuery)

All options generates similar data and use the memory store outcome, that is they return something like:

{
  records: [ [...], [...], ... ],
  metadata: { may be some metadata e.g. file name }
  useMemoryStore: true
}
  my.fetch = function(dataset) {
    var dfd = new Deferred();
    if (dataset.file) {
      var reader = new FileReader();
      var encoding = dataset.encoding || 'UTF-8';
      reader.onload = function(e) {
        var rows = my.parseCSV(e.target.result, dataset);
        dfd.resolve({
          records: rows,
          metadata: {
            filename: dataset.file.name
          },
          useMemoryStore: true
        });
      };
      reader.onerror = function (e) {
        alert('Failed to load file. Code: ' + e.target.error.code);
      };
      reader.readAsText(dataset.file, encoding);
    } else if (dataset.data) {
      var rows = my.parseCSV(dataset.data, dataset);
      dfd.resolve({
        records: rows,
        useMemoryStore: true
      });
    } else if (dataset.url) {
      jQuery.get(dataset.url).done(function(data) {
        var rows = my.parseCSV(data, dataset);
        dfd.resolve({
          records: rows,
          useMemoryStore: true
        });
      });
    }
    return dfd.promise();
  };

parseCSV

Converts a Comma Separated Values string into an array of arrays. Each line in the CSV becomes an array.

Empty fields are converted to nulls and non-quoted numbers are converted to integers or floats.

@return The CSV parsed as an array @type Array

@param {String} s The string to convert @param {Object} options Options for loading CSV including @param {Boolean} [trim=false] If set to True leading and trailing whitespace is stripped off of each non-quoted field as it is imported @param {String} [delimiter=','] A one-character string used to separate fields. It defaults to ',' @param {String} [quotechar='"'] A one-character string used to quote fields containing special characters, such as the delimiter or quotechar, or which contain new-line characters. It defaults to '"'

Heavily based on uselesscode's JS CSV parser (MIT Licensed): http://www.uselesscode.org/javascript/csv/

  my.parseCSV= function(s, options) {

Get rid of any trailing \n

    s = chomp(s);

    var options = options || {};
    var trm = (options.trim === false) ? false : true;
    var delimiter = options.delimiter || ',';
    var quotechar = options.quotechar || '"';

    var cur = '', // The character we are currently processing.
      inQuote = false,
      fieldQuoted = false,
      field = '', // Buffer for building up the current field
      row = [],
      out = [],
      i,
      processField;

    processField = function (field) {
      if (fieldQuoted !== true) {

If field is empty set to null

        if (field === '') {
          field = null;

If the field was not quoted and we are trimming fields, trim it

        } else if (trm === true) {
          field = trim(field);
        }

Convert unquoted numbers to their appropriate types

        if (rxIsInt.test(field)) {
          field = parseInt(field, 10);
        } else if (rxIsFloat.test(field)) {
          field = parseFloat(field, 10);
        }
      }
      return field;
    };

    for (i = 0; i < s.length; i += 1) {
      cur = s.charAt(i);

If we are at a EOF or EOR

      if (inQuote === false && (cur === delimiter || cur === "\n")) {
  field = processField(field);

Add the current field to the current row

        row.push(field);

If this is EOR append row to output and flush row

        if (cur === "\n") {
          out.push(row);
          row = [];
        }

Flush the field buffer

        field = '';
        fieldQuoted = false;
      } else {

If it's not a quotechar, add it to the field buffer

        if (cur !== quotechar) {
          field += cur;
        } else {
          if (!inQuote) {

We are not in a quote, start a quote

            inQuote = true;
            fieldQuoted = true;
          } else {

Next char is quotechar, this is an escaped quotechar

            if (s.charAt(i + 1) === quotechar) {
              field += quotechar;

Skip the next char

              i += 1;
            } else {

It's not escaping, so end quote

              inQuote = false;
            }
          }
        }
      }
    }

Add the last field

    field = processField(field);
    row.push(field);
    out.push(row);

    return out;
  };

serializeCSV

Convert an Object or a simple array of arrays into a Comma Separated Values string.

Nulls are converted to empty fields and integers or floats are converted to non-quoted numbers.

@return The array serialized as a CSV @type String

@param {Object or Array} dataToSerialize The Object or array of arrays to convert. Object structure must be as follows:

{
  fields: [ {id: .., ...}, {id: ..., 
  records: [ { record }, { record }, ... ]
  ... // more attributes we do not care about
}

@param {object} options Options for serializing the CSV file including delimiter and quotechar (see parseCSV options parameter above for details on these).

Heavily based on uselesscode's JS CSV serializer (MIT Licensed): http://www.uselesscode.org/javascript/csv/

  my.serializeCSV= function(dataToSerialize, options) {
    var a = null;
    if (dataToSerialize instanceof Array) {
      a = dataToSerialize;
    } else {
      a = [];
      var fieldNames = _.pluck(dataToSerialize.fields, 'id');
      a.push(fieldNames);
      _.each(dataToSerialize.records, function(record, index) {
        var tmp = _.map(fieldNames, function(fn) {
          return record[fn];
        });
        a.push(tmp);
      });
    }
    var options = options || {};
    var delimiter = options.delimiter || ',';
    var quotechar = options.quotechar || '"';

    var cur = '', // The character we are currently processing.
      field = '', // Buffer for building up the current field
      row = '',
      out = '',
      i,
      j,
      processField;

    processField = function (field) {
      if (field === null) {

If field is null set to empty string

        field = '';
      } else if (typeof field === "string" && rxNeedsQuoting.test(field)) {

Convert string to delimited string

        field = quotechar + field + quotechar;
      } else if (typeof field === "number") {

Convert number to string

        field = field.toString(10);
      }

      return field;
    };

    for (i = 0; i < a.length; i += 1) {
      cur = a[i];

      for (j = 0; j < cur.length; j += 1) {
        field = processField(cur[j]);

If this is EOR append row to output and flush row

        if (j === (cur.length - 1)) {
          row += field;
          out += row + "\n";
          row = '';
        } else {

Add the current field to the current row

          row += field + delimiter;
        }

Flush the field buffer

        field = '';
      }
    }

    return out;
  };

  var rxIsInt = /^\d+$/,
    rxIsFloat = /^\d*\.\d+$|^\d+\.\d*$/,

If a string has leading or trailing space, contains a comma double quote or a newline it needs to be quoted in CSV output

    rxNeedsQuoting = /^\s|\s$|,|"|\n/,
    trim = (function () {

Fx 3.1 has a native trim function, it's about 10x faster, use it if it exists

      if (String.prototype.trim) {
        return function (s) {
          return s.trim();
        };
      } else {
        return function (s) {
          return s.replace(/^\s*/, '').replace(/\s*$/, '');
        };
      }
    }());

  function chomp(s) {
    if (s.charAt(s.length - 1) !== "\n") {

Does not end with \n, just return string

      return s;
    } else {

Remove the \n

      return s.substring(0, s.length - 1);
    }
  }


}(this.recline.Backend.CSV));