Time: 0:00
Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).
This bug belongs to the type errors pattern
Totals that concatenate, sorts that put 10 before 9, comparisons that refuse to run.
What went wrong: Number.prototype.toFixed() returns a string. Using + between a number and string performs string concatenation.
The fix: Cast the toFixed() string back to a number: Number((subtotal * taxRate).toFixed(2))
Remember: In JavaScript, toFixed() always returns a string; wrap with Number() before arithmetic.
The pattern behind it: type errors.
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<iframe src="https://trybughunt.com/embed/d70b94c7-c5b5-45d7-b4e1-b5d3cd4bdae7" title="Debugging challenge: Adding toFixed result to number performs string concatenation" width="100%" height="580" loading="lazy" style="border:1px solid #d4d4d8;border-radius:12px;max-width:760px"></iframe>
<p style="font-size:14px">Debugging challenge from <a href="https://trybughunt.com/challenges/d70b94c7-c5b5-45d7-b4e1-b5d3cd4bdae7">TryBugHunt</a></p>