[devknight-ink]

Problem

SwapWidgetRenderer, DepositAddressModalRenderer and OnrampModal build their quote parameters eagerly on every render and call viem's parseUnits() on the raw (debounced) amount input. That value is '' on first mount (when no defaultAmount is set), after the user clears the field, and after every completed swap (setAmountInputValue('')).

viem ≤ 2.55.2 returned 0n for parseUnits(''). From viem 2.55.4 (utils/unit/Value.ts, from()), any value without a digit — '', '.', '-' — throws Value.InvalidDecimalNumberError. Nothing catches it in the render path, so React unmounts the whole tree:

Value.InvalidDecimalNumberError: Value '' is not a valid decimal number

The repo's own lockfile resolves viem 2.52.2, which is why the demo does not show it. Integrators on a current viem (>=2.26.0 is the declared peer range) see the widget crash on load or immediately after a swap.

Reproduction: mount <SwapWidget /> with viem 2.57.x installed, delete the 0 in the amount field (or complete a swap).

Fix

• Add parseUnitsOrZero(value, decimals) to utils/numbers.ts: returns 0n when the trimmed value consists only of -/./nothing (empty or mid-edit input), otherwise defers to parseUnits, so genuinely malformed input still throws as before.
• Use it at the three quote-parameter call sites. The quote hooks were already disabled for a zero amount, so request behaviour is unchanged.

Verification

• pnpm run typecheck (packages/ui), eslint on the changed files and scripts/lint-changesets.mjs pass.
• Behaviour matrix against viem 2.57.10:

input	parseUnits	parseUnitsOrZero
'', '.', '-', undefined	throws	0n
'0.', '0.01', '12.5', 5	ok	same result
'abc', '1e3'	throws	still throws

Changeset included (patch, @relayprotocol/relay-kit-ui).

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[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge.

Summary

The PR adds parseUnitsOrZero and uses it when building swap, deposit-address, and onramp quotes.

• Quote amounts treat empty input as zero across three widget flows.

No actionable issues were found. Review checks were static; no runtime tests were run.

_{Reviews (1) · Last reviewed commit: "fix(ui): treat an empty amount as zero w..." · Reviewed by Greptile}