Add bridge nav-button controller.

app/javascript/bridge/controllers/bridge/nav_button_controller.js

@@ -0,0 +1,22 @@
+import { BridgeComponent } from "@hotwired/hotwire-native-bridge"
+
+export default class extends BridgeComponent {
+  static component = "nav-button"
+
+  connect() {
+    super.connect()
+
+    if (this.bridgeElement.enabled) {
+      this.notifyBridgeOfConnect()
+    }
+  }
+
+  notifyBridgeOfConnect() {
+    const navButton = this.bridgeElement.getButton()
+    navButton.displayAsFormSubmitMenu = this.bridgeElement.shouldDisplayAsFormSubmitMenu()
+
+    this.send("connect", navButton, () => {
+      this.element.click()
+    })
+  }
+}

app/javascript/bridge/initializers/bridge_element.js

@@ -11,3 +11,35 @@ BridgeElement.prototype.showOnPlatform = function() {
 BridgeElement.prototype.hideOnPlatform = function() {
   this.element.classList.add("hide-on-native")
 }
+
+BridgeElement.prototype.getButton = function() {
+  return {
+    title: this.title,
+    icon: this.getIcon(),
+    label: this.getLabel(),
+    order: this.getOrder()
+  }
+}
+
+BridgeElement.prototype.getIcon = function() {
+  const name = this.bridgeAttribute("icon-name")
+  const url = this.bridgeAttribute(`icon-${this.platform}-url`)
+
+  if (name || url) {
+    return { name, url }
+  }
+
+  return null
+}
+
+BridgeElement.prototype.getLabel = function() {
+  return this.bridgeAttribute("label")
+}
+
+BridgeElement.prototype.getOrder = function() {
+  return this.bridgeAttribute("order") || "1"
+}
+
+BridgeElement.prototype.shouldDisplayAsFormSubmitMenu = function() {
+  return this.bridgeAttribute("display-as-form-submit-menu") === "true"
+}