refs (#100)

* refs

* React.DOM.Props.ref - set ref property (string)
* React.readRef - read ref through Foreign

* readRef from Foreign rather than Refs

* React.DOM.Props.refCb

* readRef and writeRef through ffi

* Remove DOM dependency, use foreign data type for Ref

Still adds two small dependencies
* purescript-maybe
* purescript-nullable

* Rename: withRef && added comments.

* Nullable Ref in withRefs

Author: Marcin Szamotulski

bower.json

@@ -19,7 +19,9 @@
   "dependencies": {
     "purescript-eff": "^3.0.0",
     "purescript-prelude": "^3.0.0",
-    "purescript-unsafe-coerce": "^3.0.0"
+    "purescript-unsafe-coerce": "^3.0.0",
+    "purescript-maybe": "^3.0.0",
+    "purescript-nullable": "^3.0.0"
   },
   "devDependencies": {
     "purescript-console": "^3.0.0",

src/React.js

@@ -40,6 +40,30 @@ function getChildren(this_) {
 }
 exports.getChildren = getChildren;
 
+function readRefImpl (this_) {
+  return function(name) {
+    return function() {
+      var refs = this_.refs || {};
+      return refs[name];
+    }
+  }
+}
+exports.readRefImpl = readRefImpl;
+
+function writeRef(this_) {
+  return function(name) {
+    return function(node) {
+      return function() {
+        var refs = this_.refs || {};
+        refs[name] = node;
+        this_.refs = refs;
+        return {};
+      }
+    }
+  }
+}
+exports.writeRef = writeRef;
+
 function writeState(this_) {
   return function(state){
     return function(){

src/React.purs

@@ -19,6 +19,7 @@ module React
   , ReactRefs
 
   , Refs
+  , Ref
 
   , Render
   , GetInitialState
@@ -43,6 +44,8 @@ module React
 
   , getProps
   , getRefs
+  , readRef
+  , writeRef
   , getChildren
 
   , readState
@@ -73,6 +76,8 @@ module React
 import Prelude
 
 import Control.Monad.Eff (kind Effect, Eff)
+import Data.Maybe (Maybe)
+import Data.Nullable (Nullable, toMaybe)
 import Control.Monad.Eff.Uncurried (EffFn2, runEffFn2)
 import Unsafe.Coerce (unsafeCoerce)
 
@@ -302,6 +307,30 @@ foreign import getRefs :: forall props state access eff.
   ReactThis props state ->
   Eff (refs :: ReactRefs (read :: Read | access) | eff) Refs
 
+-- | Ref type.  You can store `Ref` types on `Refs` object (which in
+-- | corresponds to `this.refs`).  Use `ReactDOM.refToNode` if you want to
+-- store a `DOM.Node.Types.Node`
+foreign import data Ref :: Type
+
+foreign import readRefImpl :: forall props state access eff.
+  ReactThis props state ->
+  String ->
+  Eff (refs :: ReactRefs (read :: Read | access) | eff) (Nullable Ref)
+
+-- | Read named ref from `Refs`.
+readRef :: forall props state access eff.
+  ReactThis props state ->
+  String ->
+  Eff (refs :: ReactRefs (read :: Read | access) | eff) (Maybe Ref)
+readRef this name = toMaybe <$> readRefImpl this name
+
+-- | Write a `Ref` to `Refs`
+foreign import writeRef :: forall props state access eff.
+  ReactThis props state ->
+  String ->
+  Nullable Ref ->
+  Eff (refs :: ReactRefs (write :: Write | access) | eff) Unit
+
 -- | Read the component children property.
 foreign import getChildren :: forall props state eff.
   ReactThis props state ->

src/React/DOM/Props.purs

@@ -1,6 +1,10 @@
 module React.DOM.Props where
 
-import React (Event, EventHandlerContext, KeyboardEvent, MouseEvent, handle)
+import Control.Monad.Eff (Eff)
+import Control.Monad.Eff.Unsafe (unsafePerformEff)
+import Data.Nullable (Nullable)
+import Prelude (Unit, (<<<))
+import React (Event, EventHandlerContext, KeyboardEvent, MouseEvent, ReactRefs, Ref, Write, handle)
 
 foreign import data Props :: Type
 
@@ -297,6 +301,19 @@ radioGroup = unsafeMkProps "radioGroup"
 readOnly :: Boolean -> Props
 readOnly = unsafeMkProps "readOnly"
 
+ref :: String -> Props
+ref = unsafeMkProps "ref"
+
+-- | You can use `writeRef` to store a reference on `Refs`.
+-- | ``` purescrript
+-- | div [ withRef (writeRef this "inputElement") ] [...]
+-- | ```
+withRef
+  :: forall access eff
+   . (Nullable Ref -> Eff (refs :: ReactRefs (write :: Write | access) | eff) Unit)
+  -> Props
+withRef cb = unsafeMkProps "ref" (unsafePerformEff <<< cb)
+
 rel :: String -> Props
 rel = unsafeMkProps "rel"