[Testing] useSettings localStorage persistence and formatAmountWithPreference are untested

[grantfox-oss]

Telegram (ask questions / claim the issue here first): https://t.me/+DOylgFv1jyJlNzM0

Why this matters

src/hooks/useSettings.ts persists theme/displayCurrency/amountFormat/decimalPlaces to localStorage, applies the theme class, and exports formatAmountWithPreference() which does bigint scaling and truncates to the user's decimalPlaces preference. This formatter feeds amount display and is untested - fractional truncation to 2/4/7 places and trailing-zero trimming have no coverage.

Acceptance criteria

• Test setTheme/setDecimalPlaces etc. write the expected STORAGE_KEYS values and update state
• Test the hook hydrates settings from pre-seeded localStorage values
• Test formatAmountWithPreference truncates to 2/4/7 decimals, trims trailing zeros, and handles bigint/number/string inputs

Files to touch

• frontend/src/hooks/useSettings.ts

Out of scope

• Settings page label/htmlFor a11y

[heymide]

@heymide has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Interested in working on this issue. I'll implement the requested changes and ensure everything is properly tested before submission.

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[MorsH14]

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Id love to work on this issue

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[Oluwasuyi-Oluwatimilehin-Daniel]

@Oluwasuyi-Timilehin has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

hello maintainer, please assign me to this task. I would get started immediately

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[Oyixah]

@Oyixah has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi, can I work on this please?

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[david87131]

@david87131 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Interested in working on this issue. I'll implement the requested changes and ensure everything is properly tested before submission.

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[DevSolex]

@DevSolex has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi Maintainer,

I’m a smart contract and full-stack developer and would love to contribute to this issue. I’m an experienced contributor with hands-on expertise in Rust, Soroban, Cairo, and TypeScript.

I’m passionate about building secure, scalable blockchain solutions, with a strong emphasis on writing clean and maintainable code. Based on the scope of this issue, I’m confident I can deliver a complete solution within 24 hours of assignment.

I’d greatly appreciate the opportunity to contribute and help move this forward.

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[ZuLu0890]

@ZuLu0890 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would love to work on this issue

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[drips-wave]

Congratulations, @david87131! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @david87131: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

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[grantfox-oss]

🦊 GrantFox — @david87131 has been assigned to this issue!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #882)
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Good luck! Track your progress on GrantFox.