More specific types for ReactTag

Author: oyvindberg

core/src/main/scala/japgolly/scalajs/react/vdom/Extra.scala

@@ -50,7 +50,7 @@ object Extra {
   final class StringExt(private val s: String) extends AnyVal {
     @inline def reactAttr : Attr     = Attr(s)
     @inline def reactStyle: Style    = Style(s, s)
-    @inline def reactTag  : ReactTag = makeAbstractReactTag(s, Scalatags.NamespaceHtml.implicitNamespace)
+    @inline def reactTag[N <: TopNode]: ReactTagOf[N] = makeAbstractReactTag(s, Scalatags.NamespaceHtml.implicitNamespace)
   }
 
   trait Tags {

core/src/main/scala/japgolly/scalajs/react/vdom/Implicits.scala

@@ -66,8 +66,8 @@ abstract class Implicits extends LowPri {
   @inline implicit final def _react_cssNumber    [T: Numeric](t: T): CssNumber       = new CssNumber(t)
 
   // Rendering
-  @inline implicit final def _react_autoRender (t: ReactTag)     : ReactElement      = t.render
-  @inline implicit final def _react_autoRenderS(t: Seq[ReactTag]): Seq[ReactElement] = t.map(_.render)
+  @inline implicit final def _react_autoRender [T <: TopNode](t: ReactTagOf[T])     : ReactElement      = t.render
+  @inline implicit final def _react_autoRenderS[T <: TopNode](t: Seq[ReactTagOf[T]]): Seq[ReactElement] = t.map(_.render)
 
   // Extensions
   @inline implicit final def _react_ext_attr(a: Attr)    = new Extra.AttrExt(a)

core/src/main/scala/japgolly/scalajs/react/vdom/Scalatags.scala

@@ -1,13 +1,12 @@
 package japgolly.scalajs.react.vdom
 
-import org.scalajs.dom
 import scala.annotation.{elidable, implicitNotFound}
 import scala.scalajs.js
 import japgolly.scalajs.react._
 import Scalatags._
 
 /**
- * Represents a value that can be nested within a [[ReactTag]]. This can be
+ * Represents a value that can be nested within a [[ReactTagOf]]. This can be
  * another [[TagMod]], but can also be a CSS style or HTML attribute binding,
  * which will add itself to the node's attributes but not appear in the final
  * `children` list.
@@ -34,9 +33,10 @@ object TagMod {
     TagModComposition(ms.toVector)
 }
 
-final case class ReactTag private[vdom](tag: String,
-                                        modifiers: List[Seq[TagMod]],
-                                        namespace: Namespace) extends DomFrag {
+final case class ReactTagOf[+N <: TopNode] private[vdom](
+  tag:       String,
+  modifiers: List[Seq[TagMod]],
+  namespace: Namespace) extends DomFrag {
 
   def render: ReactElement = {
     val b = new Builder()
@@ -71,7 +71,7 @@ final case class ReactTag private[vdom](tag: String,
     }
   }
 
-  def apply(xs: TagMod*): ReactTag =
+  def apply(xs: TagMod*): ReactTagOf[N] =
     this.copy(tag = tag, modifiers = xs :: modifiers)
 
   override def toString = render.toString
@@ -215,9 +215,9 @@ private[vdom] object Scalatags {
     override def apply(b: Builder, s: Style, t: T[A]) = ot.foreach(t)(v(b, s, _))
   }
 
-  @inline def makeAbstractReactTag(tag: String, namespaceConfig: Namespace): ReactTag = {
+  @inline def makeAbstractReactTag[N <: TopNode](tag: String, namespaceConfig: Namespace): ReactTagOf[N] = {
     Escaping.assertValidTag(tag)
-    ReactTag(tag, Nil, namespaceConfig)
+    ReactTagOf[N](tag, Nil, namespaceConfig)
   }
 
   implicit final class SeqFrag[A <% Frag](xs: Seq[A]) extends Frag {
@@ -258,16 +258,16 @@ private[vdom] object Scalatags {
 
   implicit class STStringExt(private val s: String) extends AnyVal {
     /**
-     * Converts the string to a [[ReactTag]]
+     * Converts the string to a [[ReactTagOf]]
      */
-    def tag[N <: dom.Node](implicit namespaceConfig: Namespace): ReactTag =
+    def tag[N <: TopNode](implicit namespaceConfig: Namespace): ReactTagOf[N] =
       makeAbstractReactTag(s, namespaceConfig)
 
     /**
-     * Converts the string to a void [[ReactTag]]; that means that they cannot
+     * Converts the string to a void [[ReactTagOf]]; that means that they cannot
      * contain any content, and can be rendered as self-closing tags.
      */
-    def voidTag[N <: dom.Node](implicit namespaceConfig: Namespace): ReactTag =
+    def voidTag[N <: TopNode](implicit namespaceConfig: Namespace): ReactTagOf[N] =
       makeAbstractReactTag(s, namespaceConfig)
 
     /**
@@ -284,7 +284,7 @@ private[vdom] object Scalatags {
   }
 
   /**
-   * Allows you to modify a [[ReactTag]] by adding a Seq containing other nest-able
+   * Allows you to modify a [[ReactTagOf]] by adding a Seq containing other nest-able
    * objects to its list of children.
    */
   implicit class SeqNode[A <% TagMod](xs: Seq[A]) extends TagMod {

core/src/main/scala/japgolly/scalajs/react/vdom/package.scala

@@ -19,7 +19,7 @@ package object vdom {
 
   // If you're wondering why abstract class instead of trait, https://issues.scala-lang.org/browse/SI-4767
   abstract class Base extends Implicits {
-    final type ReactTag = japgolly.scalajs.react.vdom.ReactTag
+    final type ReactTag = japgolly.scalajs.react.vdom.ReactTagOf[TopNode]
     final type TagMod   = japgolly.scalajs.react.vdom.TagMod
     @inline final def TagMod   = japgolly.scalajs.react.vdom.TagMod
     @inline final def EmptyTag = japgolly.scalajs.react.vdom.EmptyTag

extra/src/main/scala/japgolly/scalajs/react/extra/router/RouterCtl.scala

@@ -2,7 +2,9 @@ package japgolly.scalajs.react.extra.router
 
 import japgolly.scalajs.react._
 import japgolly.scalajs.react.extra.Reusability
+import japgolly.scalajs.react.vdom.ReactTagOf
 import japgolly.scalajs.react.vdom.prefix_<^._
+import org.scalajs.dom.html
 
 /**
  * Router controller. A client API to the router.
@@ -25,7 +27,7 @@ abstract class RouterCtl[A] {
   final def setOnClick(target: A): TagMod =
     ^.onClick ==> setEH(target)
 
-  final def link(target: A): ReactTag =
+  final def link(target: A): ReactTagOf[html.Anchor] =
     <.a(^.href := urlFor(target).value, setOnClick(target))
 
   final def contramap[B](f: B => A): RouterCtl[B] =