Graph Compose

Template Syntax & Node Communication 🔄

Build powerful workflows by connecting your nodes with our intuitive template syntax. Learn how to share and transform data between nodes using handlebars expressions.

🚀 TLDR: Use handlebars syntax {{expression}} to access node results, context data, and transform values using JSONata. That's all you need to know to get started!

Why Care About Node Communication? 🤔

Node communication is the backbone of powerful workflows:

  • 🔗 Chain API calls (pass auth tokens from login to subsequent requests)
  • 🎯 Build dynamic URLs (use user IDs from one API to fetch their orders)
  • 🛠️ Combine data (merge user profile with their latest orders)
  • 🔒 Share secrets (use API keys from context across multiple requests)
  • 🚀 Transform responses (reshape API responses to match your needs)

💡 Think of nodes as team members - the better they communicate, the smoother your workflow runs!

Using Template Syntax ✨

Every node can access results from previous nodes using handlebars syntax:

import { GraphCompose } from '@graphcompose/sdk';

const workflow = new GraphCompose()
  .addHttpNode('send_welcome_email')
  .withBody({
    to: '{{ results.create_user.email }}',        // Access email from previous node
    name: '{{ results.create_user.firstName }}'   // Access name from previous node
  });

Sharing Context 🌍

Need to share data across your whole workflow? Access the global context:

import { GraphCompose } from '@graphcompose/sdk';

const workflow = new GraphCompose()
  .setContext({
    apiKey: process.env.API_KEY,              // Available to all nodes
    baseUrl: "https://api.example.com"        // Shared configuration
  })
  .addHttpNode('make_request')
  .withHeaders({
    'x-api-key': '{{ context.apiKey }}'      // Access from context
  })
  .get('{{ context.baseUrl }}/users');       // Build URL dynamically

Transforming Data 🔄

Need to reshape data between nodes? Use JSONata expressions inside handlebars:

import { GraphCompose } from '@graphcompose/sdk';

const workflow = new GraphCompose()
  .addHttpNode('prepare_order')
  .withBody({
    userId: '{{ results.get_user.id }}',  // Access nested result data
    items: '{{ results.get_cart.items.{ "productId": id, "quantity": quantity, "price": price * quantity } }}',  // Transform array items
    total: '{{ $sum(results.get_cart.items.(price * quantity)) }}'  // Calculate total using JSONata
  });

Common Patterns 💫

Here are some cool ways nodes can work together:

Building Request Data 🏗️

import { GraphCompose } from '@graphcompose/sdk';

const workflow = new GraphCompose()
  .addHttpNode('create_order')
  .withBody({
    user: '{{ results.get_user }}',      // Include entire user object
    items: '{{ results.get_cart.items }}', // Array of cart items
    shipping: '{{ results.get_address }}' // Full shipping details
  });

Passing Authentication 🔐

import { GraphCompose } from '@graphcompose/sdk';

const workflow = new GraphCompose()
  .addHttpNode('authenticated_request')
  .withHeaders({
    Authorization: '{{ $concat("Bearer ", results.get_token.access_token) }}'  // Combine token with prefix
  });

Best Practices 💡

Keep your node communication clean and efficient:

  • 🎯 Make dependencies clear and explicit
  • 📝 Use descriptive node IDs
  • 🔍 Keep transformations simple and focused
  • ✨ Validate data between critical steps
  • 🎨 Structure workflows for easy data flow

Want to learn more about JSONata?

JSONata is a powerful query language for JSON data. You can visit JSONata.org for more information and a playground to test your expressions.

Visit the JSONata website
Learn More About Expressions in our Deep Dive on JSONata ✨