Coding Challenge #66: JavaScript Countdown Timer

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The Coding Train

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Published on March 25, 2017 1:46:28 PM ● Video Link: https://www.youtube.com/watch?v=MLtAMg9_Svw

Duration: 21:48

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In this video, I use the p5.js library to create a web-based countdown timer. I discuss the native JavaScript method setInterval() and well as p5’s millis(). Code: https://thecodingtrain.com/challenges/66-javascript-countdown-timer

🕹️ p5.js Web Editor Sketch: https://editor.p5js.org/codingtrain/sketches/ZKSNy0USh

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References:
🔗 millis() reference: https://p5js.org/reference/#/p5/millis
🔗 getURLParams() reference: https://p5js.org/reference/#/p5/getURLParams
🔴 Coding Train Live 87: https://youtu.be/hVSHlFjTeqg?t=1355s

Related Coding Challenges:
🚂 #74 Clock: https://youtu.be/E4RyStef-gY

Timestamps:
0:00 Introduction
0:52 Describe challenge
1:56 Let's code
2:12 Display timer
3:50 Decide what to display
4:12 Introduce setInterval
5:10 Mention requestAnimationFrame
5:30 Increment counter with setInterval
6:15 Count backwards
7:38 Choose to display minutes and seconds
8:08 Calculate minutes with floor
9:10 Calculate seconds with modulo
10:04 Display minutes and seconds
10:45 Format values with nf
11:50 Describe URL query parameters
12:34 Get parameters with getURLparams
13:40 Handle missing parameter
14:43 Handle minute parameter
15:18 Add sound
16:22 Stop timer
16:58 Stop interval with clearInterval
17:18 Test timer
17:40 Conclusion and creative possibilities
18:10 Addendum: refine timer with millis
18:58 Replace counter with current time
19:49 Debugging
20:45 Conclusion

Editing by Mathieu Blanchette
Animations by Jason Heglund
Music from Epidemic Sound

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#countdowntimer #setinterval #p5js #javascript