#Variable Basics

#What is a Variable?

Imagine you're building a complex Lego model where each module needs to connect precisely. In the world of Workflows, variables play a similar role as "connectors." They are the "messengers" used to pass information between different nodes.

Simply put, a variable is a named container where you can store various things, such as user input, calculation results, or data retrieved from somewhere.

A variable typically consists of three parts:

• Name (Unique Identifier): Like your name, it allows everyone to find this variable accurately. For example, userName, orderId.
• Value: The content inside the container. It can be a number 123, text "Hello Flowgram!", or a switch state true / false.
• Type: Specifies what kind of things this container can hold. For instance, some can only hold numbers, while others can only hold text.

For example, in an "Intelligent Q&A" flow:

1. WebSearch Node: Responsible for searching the web and putting the found knowledge (e.g., the answer to "What's the weather like today?") into a variable named natural_language_desc.

2. LLM Node: It takes the natural_language_desc "messenger," reads its content, and then answers the user in a more natural and friendly way.

3. In this process, the type of natural_language_desc is "string" because it contains text content.

#Why Do You Need a Variable Engine?

As the complexity of workflows increases, so do the number and management difficulty of variables.

To address this challenge, Flowgram provides a powerful Variable Engine.

It acts like a professional "data steward," systematically managing all variables to ensure the clarity and stability of the data flow.

Enabling the Variable Engine will bring you the following core advantages:

Scope Constraints: Precise Data Access Control

The Variable Engine can precisely control the effective range (i.e., scope) of each variable. Like having specific keys for different rooms, it ensures that variables are only accessed within the intended nodes, effectively preventing data pollution and unexpected logical errors.

The query variable defined in the Start node can be easily accessed by the subsequent LLM and End nodes.

The LLM node is in a Condition branch, like being in a separate room. The End node outside naturally cannot access its result variable.

Variable Structure Insight: Easily Understand Complex Data

When a variable becomes complex (e.g., an object with many levels), the Variable Engine allows you to explore its internal structure layer by layer, like peeling an onion, with all details at your fingertips.

In this diagram, you can see the output variables of all nodes and their hierarchical relationships, like a lush tree.

Automatic Type Inference: A Spark of Genius

You no longer need to tell each variable what its type should be. The Variable Engine, like your "soulmate," will automatically infer its type based on the context.

For example, when the type of the arr variable in the Start node changes, the type of the item output by the Batch node will also be automatically updated to ensure type consistency.

#How to Enable the Variable Engine?

You can enable the Variable Engine with a simple configuration to experience its powerful features.

> View API Details

// Enable the Variable Engine in EditorProps
{
  variableEngine: {
    // Set to true to enable the Variable Engine
    enable: true
  }
}