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Print

The Print node allows you to print messages into the app logs. It's a useful tool for debugging and tracking variable values or function outputs during runtime.

💡 Common use cases for Print:​

  • Debugging: see the value of a variable or the result of an expression.

  • Validating user input: print what a user typed in a form field.

  • Monitoring app behavior: check if a certain function or condition was triggered.

  • Logging custom events: record actions like button clicks, page visits, etc.

➕ How to add a Print node​

  1. Inside the Circuit, scroll down to the Nowa category.

  2. Drag and drop the Print node into your circuit.

  3. Next to the Msg field:

    • You can directly type the message to print.

    • Or click on Msg to connect it to a variable, parameter, or an expression.

🔍 Viewing Printed Messages​

When you run your app:

  • Click the log icon in the bottom-left corner of the Nowa editor.

  • A popup will open showing logs (default tab is Errors—click on Logs to view your print outputs).

📹 In the example video, we simply added a Print node with a plain message and confirmed it appears in the logs as expected.

💻 Local Projects and External Logs

If you're running your app on a simulator (e.g., iOS simulator):

  • You'll see printed messages inside Nowa

  • Also in external tools like VS Code, if you run the simulator from there.
    This is because the Print node directly uses Flutter's print() inside the generated code.

🧪 Using a variable with the printed message​

📹 In the following video:

  • We have a TextField where the user types their name.

  • We're using a TextController to access that input.

  • Then we add a Print node, and connect its Msg to the text property of the TextField, so we print the most recent name typed by the user.

🧵 Combining Text + Variables in Print​

You can print a mix of static text and dynamic data using two methods:

1. Inline using $​

Inside the Msg field:

  • Start typing your message.

  • When you want to insert a variable, parameter, or expression, just type $.

  • This will open a linking menu — select the element you want to insert.

The final message will look like message ${variable}

tip

You can inject variables, parameters, and even function results into the message. For example we can inject the result coming from calling a funciton getName like this:

"My name is ${getName()}"
tip

Note: You can use the dollar sign without curly braces if you're inserting a simple variable or parameter without any property access:

"My name is $name"

However, when referencing something that includes a dot (like accessing a property), you must wrap it with ${}, for example:

"My name is ${textController.text}"

This is the same as using ${} in Flutter (called string interpolation), where you embed code inside a string:

print("My name is ${textController.text}");

2. Using a Custom Expression​

  • Click on Msg → choose Custom expression.

  • You can build the message like:

"My name is " + textController.text
  • Or again, use string interpolation:
"My name is ${textController.text}"
The String in a custom expression should be with double quotes

Note: When using Custom expression, the entire expression must be a string, so you need to wrap it with double quotes, like:

"My name is ${textController.text}"

However, when typing directly inside the Msg field, Nowa automatically wraps your input with double quotes — so you don’t need to add them yourself. Just type your message normally.

📹 In the continuation video:

  • We first print the name from the TextField.

  • Then switch to using a custom expression to enhance the message format.