Creating Custom Nodes

Video Lecture

Section	Video Links
Creating Custom Nodes

Description

This introductory tutorial will show you how you can begin to create your own ComfyUI custom nodes.

We will build a basic calculator, which will demonstrate,

• naming your custom node,
• using various inputs such as string, float and a dropdown,
• calling a function,
• utilize output type matching to improve node output suggestions.

This is a free introductory tutorial on a very specialized subject. If you want to know more, then consider becoming a member of my SBCODE YouTube channel and I can continue to schedule and build more videos about these more specialized subjects.

Create the Custom Node

1. In your ComfyUI/custom_nodes folder, create a new folder named ComfyUI-Calculator.

2. Create a new file named __init__.py and copy/paste this code below, into it.

class CalculatorNode:
    @classmethod
    def INPUT_TYPES(cls):
        return {
            "required": {
                "number1": ("FLOAT", {"default": 0.0}),
                "number2": ("FLOAT", {"default": 0.0}),
                "operation": ("STRING", ),
                #"operation": (["+", "-", "*", "/", "%"], ),
            }
        }

    RETURN_TYPES = ("STRING",)
    #RETURN_TYPES = ("*",)
    FUNCTION = "calculate"
    CATEGORY = "SBCODE"

    def calculate(self, number1, number2, operation):
        try:
            if operation == "+":
                result = number1 + number2
            elif operation == "-":
                result = number1 - number2
            elif operation == "*":
                result = number1 * number2
            elif operation == "/":
                if number2 == 0:
                    return ("Error: Division by zero",)
                result = number1 / number2
            elif operation == "%":
                result = number1 % number2
            else:
                return ("Error: Unknown operation",)

            return (f"Result: {result}",)
        except Exception as e:
            return (f"Error: {str(e)}",)


NODE_CLASS_MAPPINGS = {
    "CalculatorNode": CalculatorNode
}

NODE_DISPLAY_NAME_MAPPINGS = {
    "CalculatorNode": "Basic Calculator"
}