Description

The Sell (off-ramp) flow displayed incorrect fiat balances for the selected asset. For example, a balance of 0.02319 BNB worth roughly $14 was shown as ~54. The wrong value was not a currency-symbol mismatch — the amount itself was off by a large factor regardless of the selected fiat currency.

The root cause is in the useBalance hook used by BuildQuote. It read the native-currency conversion rate (selectConversionRate) and the token exchange rates (selectContractExchangeRates) from the globally selected network rather than from the asset's own chain. In the Sell flow the selected asset can live on a different chain than the active network, so the wrong native rate was applied to the balance — e.g. the Ethereum rate (~2328) applied to a BNB balance yields 0.02319 × 2328 ≈ 54 instead of 0.02319 × 600 ≈ 14.

The fix reads both rates keyed on the asset's own chainId: selectConversionRateByChainId for the native conversion rate and selectContractExchangeRatesByChainId for the token exchange rates. To resolve the asset's chainId (which may be hex, decimal, or CAIP format) to an EVM hex chainId, the logic was extracted into a shared getEvmHexChainId util in the Ramp Aggregator utils, and the existing getHexChainIdFromCryptoCurrency was refactored to delegate to it — removing a near-duplicate implementation and keeping a single source of truth. Non-EVM and unparseable chainIds resolve to undefined, so the previous behavior for those paths is preserved.

Changelog

CHANGELOG entry: Fixed incorrect fiat balances shown in the Sell (off-ramp) flow when the selected asset was on a different network than the globally selected one.

Related issues

Fixes: https://consensyssoftware.atlassian.net/browse/TRAM-3464

Manual testing steps

Feature: Off-ramp fiat balance conversion

  Scenario: user views the balance of an asset on a non-active network in the Sell flow
    Given the globally selected network is Ethereum Mainnet
    And the user holds a balance on a different EVM network (e.g. 0.02319 BNB on BNB Smart Chain)

    When the user opens the Sell flow and selects that asset
    Then the displayed fiat balance is converted using that asset's own native rate (≈ $14)
    And it is no longer computed with the Ethereum rate (which previously showed ≈ 54)

Screenshots/Recordings

Before

After

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  • See trace() for usage and addToken for an example

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