Solving Codewars JavaScript Task: Finding Multiples of a Number

A step-by-step guide to fix a common issue with JavaScript code that finds multiples of an integer up to a specified limit. Learn to return the correct array of multiples!
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Solving Codewars JavaScript Task: Finding Multiples of a Number

If you're a JavaScript developer, you may have encountered the challenge of writing a function that returns multiples of a given integer up to a specified limit. This task can be deceptively simple, but it often comes with common pitfalls that can confuse even seasoned programmers. In this guide, we'll explore a specific example where someone found their code not working as expected on Codewars, and we'll walk through a solution to get it right.

The Task

The goal is to create a function that takes two positive integers:

integer: The base number to find multiples of.

limit: The upper limit up to which multiples should be generated.

For instance, if the input values are (2, 6), the output should be [2, 4, 6], as these are the multiples of 2 that do not exceed 6.

Common Code Issue

Consider the following JavaScript function initially created by a user:

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

What Went Wrong?

Upon testing, the user noticed unexpected values being returned, which led to ambiguity about why their program wasn't functioning correctly. The main issue was that arr was declared outside of the function scope, which meant:

If findMultiples was called multiple times, the arr would retain values from previous calls, leading to incorrect results.

There was no return statement to yield the generated array of multiples back to the caller.

The Solution

Step-by-Step Fix

Let’s modify the existing function to address these concerns:

Declaring arr Inside the Function: This ensures that each time the function is called, arr starts empty.

Returning the Result: Instead of logging the array, we’ll return it so we can use it further.

Updated Code

Here’s the revised version of the function:

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

Explanation of Changes

New Role of arr: By declaring arr within the scope of findMultiples, the function now starts with a fresh array each time it is called.

Returning arr: This change allows the function output to be usable immediately rather than just logging it to the console, making the function more versatile.

Conclusion

By following this step-by-step approach, we've addressed the issues present in the user's function for generating multiples. It's essential to always consider the scope of your variables and ensure outputs are returned appropriately to prevent unexpected behaviors in your programs.

If you ever find yourself wrestling with similar challenges, remember to review your variable declarations and the logic flow within your functions. Happy coding!