Coding a Timer Feature

CS Principles Website and Tools Questions
1

My students want to code a timer feature into their apps in app lab. As in, a countdown. How do they do this?

Thanks,
Jason

2

Hi @jmahoney,

What a cool idea for an app! I would ask the student to think through the following:

  • What information does a timer need? current time, how long that time is displayed, maybe some more
  • Where does this information get stored? What should the variable(s) be called?
  • How does the data get updated? Does it need user input or does it do it automatically? How?
  • How does the display get updated?
  • How does the user interact with it?

If you & the student think through this and realize you need more specific help with a certain step, please feel free to ask us on this thread.

Hope that helps!
–Michael K.

3

Look at the control category. There is a block timedLoop. I would guess that it isn’t very accurate but definitely close enough for government work. 1

1 An example of government work would be when I was working at the cruise missile plant. I was looking at a program that made calculations as part of the project that would deliver nuclear weapons. It was wrong, had a bug. I talked to the engineers about it and they didn’t care. It was close enough for government work.

4

well that’s specifically if your working in blocks, however may I suggest setTimeout? I’ll show my example below

/*
 * setTimeout(callback: Function, delay: number)
*/
setTimeout(function() {
 console.log("hello world")
}, 1000)

by using this method you can easily set a timer for as long as needed, however if you wish to make a consistent timer that counts down all the time showing progress, I believe @jdonwells solution would be better than mine

Hope this helps!