Add utility functions (#37)

* Add syntheticEvent EventFn

* Add mergeStyles

Author: spicydonuts

generated-docs/React/Basic/DOM.md

@@ -38,6 +38,20 @@ E.g.
 div { style: css { padding: "5px" } } [ text "This text is padded." ]
 ```
 
+#### `mergeStyles`
+
+``` purescript
+mergeStyles :: Array CSS -> CSS
+```
+
+Merge styles from right to left. Uses `Object.assign`.
+
+E.g.
+
+```
+style: mergeCSS [ (css { padding: "5px" }), props.style ]
+```
+
 #### `SharedProps`
 
 ``` purescript

generated-docs/React/Basic/Events.md

@@ -84,6 +84,12 @@ input { onChange: handler_ (setState \_ -> { value })
       }
 ```
 
+#### `syntheticEvent`
+
+``` purescript
+syntheticEvent :: EventFn SyntheticEvent SyntheticEvent
+```
+
 #### `merge`
 
 ``` purescript

src/React/Basic/DOM.js

@@ -0,0 +1,5 @@
+"use strict";
+
+exports.mergeStyles = function(styles) {
+  return Object.assign.apply(null, [ {} ].concat(styles));
+};

src/React/Basic/DOM.purs

@@ -29,6 +29,15 @@ foreign import data CSS :: Type
 css :: forall css. { | css } -> CSS
 css = unsafeCoerce
 
+-- | Merge styles from right to left. Uses `Object.assign`.
+-- |
+-- | E.g.
+-- |
+-- | ```
+-- | style: mergeCSS [ (css { padding: "5px" }), props.style ]
+-- | ```
+foreign import mergeStyles :: Array CSS -> CSS
+
 -- | Standard props which are shared by all DOM elements.
 type SharedProps specific =
   -- | `key` is not really a DOM attribute - React intercepts it

src/React/Basic/Events.purs

@@ -5,6 +5,7 @@ module React.Basic.Events
   , unsafeEventFn
   , handler
   , handler_
+  , syntheticEvent
   , merge
   , class Merge
   , mergeImpl
@@ -72,6 +73,9 @@ handler (EventFn fn) cb = mkEffFn1 $ fn >>> cb
 handler_ :: Eff (react :: ReactFX) Unit -> EventHandler
 handler_ = mkEffFn1 <<< const
 
+syntheticEvent :: EventFn SyntheticEvent SyntheticEvent
+syntheticEvent = id
+
 class Merge (rl :: RowList) fns a r | rl -> fns, rl a -> r where
   mergeImpl :: RLProxy rl -> Record fns -> EventFn a (Record r)