Reflect picked color automatically with a custom stream action

app/javascript/initializers/custom_stream_actions.js

@@ -0,0 +1,8 @@
+import { Turbo } from "@hotwired/turbo-rails"
+
+Turbo.StreamActions.set_css_variable = function() {
+  const name = this.getAttribute("name")
+  const value = this.getAttribute("value")
+
+  this.targetElements.forEach(element => element.style.setProperty(name, value))
+}

app/javascript/initializers/index.js

@@ -1 +1,2 @@
 import "initializers/current"
+import "initializers/custom_stream_actions"