Add template code for inclusion of relative dates

Setup the basic stuff for #4, once the module can be used, it can be
immediately re-used here.

consts.js

@@ -7,3 +7,11 @@ exports.MSG_ERR_CREDIT_DEBIT_TRANS = "Input is not enough or could not be parsed
 exports.MSG_ERR_STASH_TRANS = 'Input is not enough or could not be parsed\nCommand should look like: wallet stash 500';
 exports.MSG_INVALID_OPTION = 'Invalid option. Run wallet --help to learn about available options';
 exports.MSG_INVALID_DATE = 'Date should be formatted as yyyy-mm-dd. Support for other formats coming soon.';
+
+// TODO: This will be replaced by the module relative-date-reverse
+// the module will take a relative date string as input and return a list,
+// the first element will be true if the string could be parsed into a date,
+// and in this case, the second element will be the Date object
+exports.parseRelativeDate = function (relativeDateString) {
+  return [false, ''];
+};

index.js

@@ -1,6 +1,7 @@
 'use strict';
 module.exports = function (input, opts) {
   var Consts = require('./consts.js');
+  var parseRelativeDate = Consts.parseRelativeDate;
 
   var expenseObject = {
     reason: input[2],
@@ -17,7 +18,12 @@ module.exports = function (input, opts) {
     var dateRe = /(\d{4})-(\d{2})-(\d{2})/;
     var matchObject = expenseObject.date.match(dateRe);
     if (!matchObject) {
-      throw new Error(Consts.MSG_INVALID_DATE);
+      var relativeDate = parseRelativeDate(expenseObject.date);
+      if (relativeDate[0]) {
+        expenseObject.date = require('date-format').asString('yyyy-MM-dd', relativeDate[1]);
+      } else {
+        throw new Error(Consts.MSG_INVALID_DATE);
+      }
     }
   } else {
     expenseObject.date = require('date-format').asString('yyyy-MM-dd', new Date());