Add React interopt guide

Author: nojaf

data/sidebar_react_latest.json

@@ -28,6 +28,7 @@
   "Guides": [
     "beyond-jsx",
     "forwarding-refs",
-    "extensions-of-props"
+    "extensions-of-props",
+    "interopt"
   ]
 }

pages/docs/react/latest/interopt.mdx

@@ -0,0 +1,122 @@
+---
+title: Interopt
+description: "Reusing existing React components"
+canonical: "/docs/react/latest/interopt"
+---
+
+# Interopt
+
+Reusing existing React components in ReScript is straightforward. 
+This guide will walk you through the steps required to import and use React components within ReScript,
+including defining component props and handling various import scenarios.
+
+## Basic Example
+
+To reuse a React component in ReScript, create a new module, specify the component's location, and define its props.
+
+```js
+import Confetti from "react-confetti"
+
+const App = () => {
+    <Confetti width={300} height={300} />
+}
+```
+
+```res
+module Confetti = {
+  @module("react-confetti")
+  @react.component
+  external make : (~width:int, ~height: int) => React.element =  "default"
+}
+
+// Assuming we are in App.res
+@react.component
+let make = () => {
+  <Confetti width={300} height={300} />
+}
+```
+
+## Importing from Relative Paths
+
+You can import components from relative file paths using the `@module` attribute.  
+Use "default" to indicate the default export, or specify a named export if needed.
+
+### Named Export Example 
+
+```res
+// Equivalent of import { Foo } from "bar"
+module Foo = {
+  @module("bar")
+  @react.component
+  external make : () => React.element =  "Foo"
+}
+```
+
+## Defining Props Types
+
+You can define a separate type for your component's props within the module.
+
+### Props Type Example
+
+```res
+module Confetti = {
+  type confettiProps = {
+    width: int,
+    height: int,
+  }
+
+  @module("react-confetti") @react.component(: confettiProps)
+  external make: confettiProps => React.element = "default"
+}
+
+@react.component
+let make = () => {
+  <Confetti width={300} height={300} />
+}
+```
+
+## Optional Props
+
+To define optional props, use the `?` symbol.
+
+```res
+module Confetti = {
+  type confettiProps = {
+    width: int,
+    height: int,
+    initialVelocityX?: int,
+    initialVelocityY?: int,
+  }
+
+  @module("react-confetti") @react.component(: confettiProps)
+  external make: confettiProps => React.element = "default"
+}
+
+@react.component
+let make = () => {
+  <Confetti width={300} height={300} />
+}
+```
+
+## Extending Built-in DOM Nodes
+
+To accept existing DOM props for a component, extend the `JsxDOM.domProps` type.
+
+```res
+module Foo = {
+  type fooProps = {
+    ...JsxDOM.domProps,
+    customProp: string,
+  }
+
+  @module("foo") @react.component(: fooProps)
+  external make: fooProps => React.element = "default"
+}
+
+@react.component
+let make = () => {
+  <Foo width={"300px"} height={"300px"} customProp="bar" />
+}
+```
+
+In this example `width` and `height` can be set because `JsxDOM.domProps` was spread into `fooProps`.