Fix: prevent print() with no arguments from triggering browser print dialog

[sdass1918]

Resolves processing/p5.js-web-editor#3678

Changes:

• Updated src/core/environment.js
• Modified p5.prototype.print to check for empty arguments before calling window.print().
• Added a console warning when print() is called without any arguments instead of triggering the browser print dialog.

Behavior Before:

print(); // opened browser print popup
print("Hello"); // logged correctly

Behavior After:

print(); // logs a warning, no popup
print("Hello"); // logs correctly

PR Checklist

• npm run lint passes
• Inline reference is included / updated
• Unit tests are included / updated

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Thank You!

[oneplusiota]

shouldn't we print a newline character if no argument is passed.
It is a convention that is followed in java println or js console.log.

[sdass1918]

Thanks for the suggestion, @oneplusiota! 🙏

That’s a great point — following the convention of console.log() and Java’s println makes sense for consistency.

I can update the implementation so that when print() is called without any arguments, it simply prints a newline (i.e., console.log("")) instead of showing a warning.

Would you prefer that behaviour instead of the warning message? I can make the adjustment and push an update once confirmed.

[oneplusiota]

yeah this will work.

[sdass1918]

Great! I've updated the implementation so that print() with no arguments now outputs a blank line (console.log("")).
Let me know if any further tweaks are needed. 👍

[perminder-17]

From my opinion, if we write just print() , it's supposed to print() the window. I don't find that to be a bug? Probably we could improve the documentations letting the user know what does print() does with no arguments? What you think?

[oneplusiota]

@perminder-17 I disagree. Why should print work differently for different arguments. It's work is to write to the output stream. And more importantly, there is no use of the print window functionality in the p5 editor. And in case the user does want to print the page, they can do so by directly using the browser's print screen functionality.

[sdass1918]

Thanks both for your feedback — I appreciate the different perspectives here 🙏

My intent with this fix was to prevent print() with no arguments from unintentionally triggering the browser’s print dialog, since that can interrupt the sketch execution and isn’t consistent with how print() behaves elsewhere in p5.js or in typical console output functions.

I agree that consistency is important. From a usability point of view, having print() behave like console.log("") (i.e., output a blank line) seems clearer and safer than opening the print window, especially since users can explicitly call window.print() if they want that behavior.

[oneplusiota]

lgtm

[perminder-17]

I'm so sorry, but this is the intended behavior of the print() functions and these are the discussions related to it: #4272 and #2765.

Thanks for all your work on this. Keep looking at the issue section: https://github.com/processing/p5.js/issues and would be very great to ask maintainers confirmation on the issues before working.

Really thanks for your work and patience on this one.