sending arguments with buttons

mickey_megabyte

Hi all, first post!

I'm using Buttons from the p5.dom library, but have run into a problem - how do I send arguments with my button presses?

At the moment I have

myButton.mouseClicked(doStuff);

so, pressing myButton calls the doStuff function.

How do I send an argument/parameter to doStuff function? I want to do something like:

myButton.mouseClicked(doStuff(foo))

Thanks in advance :)

** edit **

i'm trying real hard to not use global variables

** edit 2 **

i've put doStuff() inside setup(), so now have access to setup's variables - but is there a better way

GoToLoop

• We can't choose what's sent out to callback functions! [-X
• B/c it's not our own program which invokes them. :(
• So, if your callback depends on something, that something should be global.
• However, you may try to reduce how global a variable is by taking advantage of closures: https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Closures
• Let's say you wanna have a p5.Vector which is only accessible from within your doStuff() function:

const doStuff = ( () => {
  const privateVec = createVector();
  return () => {
    privateVec.add(10, -20, 30);
    print(privateVec);
  };
} )();

• In that arrangement, privateVec is an exclusive closure to doStuff().
• Every time doStuff() is invoked, it should do the add() operation and print() current values x, y & z from privateVec's p5.Vector! :-bd

mickey_megabyte

thanks for your reply.

unfortunately I'm still a beginner JS coder and do not know about closures and consts.

it looks like i'm going to have to RTFM when i have time, and carry on with my inner function workaround as i have a deadline coming up.

GoToLoop

Just accept that global variables are necessary for event callbacks.
That's the same case for Processing's Java Mode too! :P

GoToLoop

const -> https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/const

Useful JS reference links:

1. https://developer.Mozilla.org/en-US/docs/Web/JavaScript
2. https://developer.Mozilla.org/en-US/docs/Web/API
3. https://developer.Mozilla.org/en-US/docs/Web/Events

mickey_megabyte

thanks once again - they look like useful links

GoToLoop

... and carry on with my inner function workaround...

P.S.: You're using closures there w/o being aware of it! :>
Any outer variables used by your inner function belong to its closure! @-)