Resolving the setInterval() Stacking Issue in JavaScript Clicker Games

Learn how to fix a common issue in JavaScript clicker games where multiple intervals stack, causing exponential currency growth.
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Why Is My JavaScript Function Executing More Times Per Second Than It Should?

If you're developing a clicker game in JavaScript, you may run into a frustrating issue where your function is executing more frequently than expected. In particular, this occurs when players can purchase upgrades that enhance their in-game currency generation. As a user continues to buy the same upgrade, the currency seemingly increases at an exponentially rising rate.

This behavior usually arises from the setInterval() function stacking on top of itself each time it's called. Let's break down the problem and explore how to solve it.

Understanding the Problem

In your code, you have an event handler associated with a button that allows players to purchase an upgrade that increases their currency generation rate. The issue arises primarily from the way you're invoking setInterval(). Each time a user purchases an upgrade, you're creating a new interval, which causes the function to execute more often than it should.

Here’s a simplified version of what's happening:

When a user buys an upgrade, perSec (the amount of currency generated per second) increases.

Each call to the upgrade function creates a new interval with setInterval(), meaning your increment1 function is called repeatedly for every upgrade purchased, compounding the frequency of execution.

The Solution: Avoiding Stacking Intervals

The goal is to ensure that setInterval() is only called once, no matter how many upgrades the user purchases. We can achieve this by checking if perSec is already greater than zero before attempting to set a new interval.

Updated Code Example

Here’s how you can modify your existing code:

[[See Video to Reveal this Text or Code Snippet]]

Key Changes Explained

Single setInterval() Invocation: The if (perSec === 0) condition ensures that setInterval(increment1, 1000) only runs the first time a player buys an upgrade. This prevents multiple intervals from being created.

Maintaining Variables: Ensuring that the state for perSec clearly reflects the current currency generation rate is crucial. You increment this variable as upgrades are purchased, but by managing when setInterval() is set, you control when the currency starts being added based on that rate.

User Feedback: Modifying the HTML elements to show the updated scores and costs informs players about their progress, enhancing the gaming experience.

Conclusion

Debugging issues related to repeated function calls in JavaScript can be tricky, especially in game development contexts. By strategically managing your intervals and ensuring that they only initialize once, you can create a smooth, predictable gaming experience.

By following the steps outlined in this guide, you can effectively control the execution rate of your currency generation functions in your clicker game, allowing for a fair and enjoyable experience for all users.

Happy coding!