Add parse function

Author: garyb

src/Data/JSDate.js

@@ -34,3 +34,9 @@ exports.dateMethodEff = function (method, date) {
     return date[method]();
   };
 };
+
+exports.parse = function (dateString) {
+  return function () {
+    return new Date(dateString);
+  };
+};

src/Data/JSDate.purs

@@ -102,6 +102,16 @@ foreign import jsdateLocal
 foreign import dateMethodEff :: forall eff a. Fn2 String JSDate (Eff eff a)
 foreign import dateMethod :: forall a. Fn2 String JSDate a
 
+-- | Attempts to parse a date from a string. The behaviour of this function is
+-- | implementation specific until ES5, so may not always have the same
+-- | behaviour for a given string. The RFC2822 and ISO8601 date string formats
+-- | should parse consistently.
+-- |
+-- | The `LOCALE` effect is present here as if no time zone is specified in the
+-- | string the current locale's time zone will be used instead.
+foreign import parse
+  :: forall eff. String -> Eff (locale :: LOCALE | eff) JSDate
+
 -- | The effect type used when indicating the current machine's date/time locale
 -- | is used in computing a value.
 foreign import data LOCALE :: !

test/Test/Main.purs

@@ -38,6 +38,10 @@ main = do
   assert $ not $ JSD.isValid $ JSD.jsdate defaultDateRecord { second = nan }
   assert $ not $ JSD.isValid $ JSD.jsdate defaultDateRecord { millisecond = nan }
 
+  log "Checking that a date constructed from a string with sensible values is valid..."
+  assert <<< JSD.isValid =<< JSD.parse "2011-10-10T14:48:00"
+  assert <<< JSD.isValid =<< JSD.parse "Thu, 01 Jan 1970 00:00:00 GMT-0400"
+
   log "Checking that a local date constructed with sensible values is valid..."
   assert <<< JSD.isValid =<< JSD.jsdateLocal defaultDateRecord