A Simple Way to Share Your Rails Config with JS

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Rails has a cornucopia of options to access configuration values in your application. JavaScript, not so much.

What I’ve done is standardized on storing and retrieving values from meta tags in the <head>:

# app/helpers/application_helper.rb  
def js_config(name, value)  
  tag.meta name: name, content: value  
end  

Use in Your Views

<% content_for :head do %>  
  <%= js_config "userId", Current.user.id %>  
<% end %>  

Access Values from Javascript

// app/javascript/helpers/configuration.js  
export function getConfig(name) {  
  return document.head  
	.querySelector(`meta[name="${name}"]`)  
	?.getAttribute("content")  
}

// Wrap global helpers  
export function getUserId() {  
  return getConfig("userId")  
}  

Why Meta Tags?

This approach avoids adding additional HTTP requests or relying on JSON blobs inserted into the page. It’s lightweight, keeps your app organized, and ensures configuration values are always accessible when you need them.

Ready to standardize your JavaScript configuration? Try this approach, and let me know how it works for you!