# formatting utilities and CAIP network support updates

[Dargon789]

Reviewer's Guide

Implements chain-specific SLIP-44 overrides for native BNB on Binance Smart Chain and opBNB in CAIP-19 asset formatting, adds regression tests, updates supported CAIP networks, and bumps the viem dependency and package version across the monorepo.

Class diagram for formatting utilities and CAIP network support updates

classDiagram
  class ExchangeUtil {
    <<module>>
    CHAIN_ASSET_INFO_MAP
    EVM_NATIVE_SLIP44_OVERRIDES
    +getApiUrl()
    +formatCaip19Asset(caipNetworkId, asset) string
  }

  class AssetUtil {
    <<module>>
    CHAIN_ASSET_INFO_MAP
    EVM_NATIVE_SLIP44_OVERRIDES
    +formatCaip19Asset(caipNetworkId, asset) string
  }

  class CaipNetworkUtil {
    <<module>>
    WC_HTTP_RPC_SUPPORTED_CHAINS
    +someNetworkHelpers()
    +WC_HTTP_RPC_SUPPORTED_CHAINS includes eip155:55931
  }

  class EVM_NATIVE_SLIP44_OVERRIDES_Map {
    <<value-object>>
    +key chainId string
    +value slip44CoinType string
    +entry 56 -> 714
    +entry 204 -> 714
  }

  ExchangeUtil --> EVM_NATIVE_SLIP44_OVERRIDES_Map : uses
  AssetUtil --> EVM_NATIVE_SLIP44_OVERRIDES_Map : uses

  class AppkitPackages {
    <<monorepo-packages>>
    +dependOnViem >= 2.45.0
    +PACKAGE_VERSION 1.8.17
  }

  AppkitPackages ..> ExchangeUtil : runtime usage
  AppkitPackages ..> AssetUtil : runtime usage
  AppkitPackages ..> CaipNetworkUtil : runtime usage

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Flow diagram for CAIP-19 asset formatting with SLIP-44 overrides

flowchart TD
  A["Call formatCaip19Asset(caipNetworkId, asset)"] --> B["ParseUtil.parseCaipNetworkId(caipNetworkId)\nextract chainNamespace, chainId"]
  B --> C["Lookup chainInfo from CHAIN_ASSET_INFO_MAP using caipNetworkId"]
  C --> D{Is asset equal to native?}

  D -- "No, non-native asset" --> E["assetNamespace = chainInfo.defaultTokenNamespace\nassetReference = asset"]
  E --> H["Build CAIP-19: chainNamespace:chainId/assetNamespace:assetReference"]

  D -- "Yes, native asset" --> F{Is chainNamespace eip155 and override exists for chainId?}

  F -- "Yes" --> G["assetNamespace = chainInfo.defaultNativeNamespace (unchanged)\nassetReference = EVM_NATIVE_SLIP44_OVERRIDES[chainId]\n(uses chain-specific SLIP-44 coin type, e.g. 714 for BNB)"]
  G --> H

  F -- "No" --> I["assetNamespace = chainInfo.defaultNativeNamespace\nassetReference = chainInfo.defaultNativeReference (existing behavior)"]
  I --> H

  H --> J["Return formatted CAIP-19 asset string"]

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File-Level Changes

Change	Details	Files
Add CAIP-19 formatting override so native BNB on Binance Smart Chain and opBNB uses SLIP-44 coin type 714 instead of the generic EVM type.	Introduce EVM_NATIVE_SLIP44_OVERRIDES map keyed by EVM chainId to SLIP-44 coin type in controllers ExchangeUtil and pay AssetUtil utilities. Update formatCaip19Asset to check for eip155 native assets in the overrides map and use the chain-specific SLIP-44 value for the assetReference when asset is 'native'. Ensure non-native assets still use the chain default token namespace and asset address without being affected by overrides.	packages/controllers/src/utils/ExchangeUtil.ts packages/pay/src/utils/AssetUtil.ts
Add tests to validate BNB CAIP-19 formatting behavior and guard against regressions.	Add tests asserting that native BNB on Binance Smart Chain (eip155:56) and opBNB (eip155:204) format to caip19 with slip44:714. Add a test confirming that ERC20 token formatting on BSC remains unchanged and not impacted by native-token overrides.	packages/controllers/tests/utils/ExchangeUtil.test.ts
Update viem dependency version and related peer dependency constraints across apps, packages, and examples, and bump appkit package version.	Bump viem from 2.44.2 to 2.45.0 in multiple app and example package.json files and in packages that depend on viem. Adjust peerDependency ranges that reference viem to require >=2.45.0. Increment PACKAGE_VERSION from 1.8.16 to 1.8.17 in appkit constants.	apps/browser-extension/package.json apps/demo/package.json apps/laboratory/package.json examples/next-ak-basic-app-router/package.json examples/next-ak-basic-sign-client-app-router/package.json examples/next-ak-basic-up-app-router/package.json examples/next-bitcoin-app-router/package.json examples/next-ep-app-router/package.json examples/next-ethers-app-router/package.json examples/next-wagmi-app-router/package.json examples/next-wagmi-solana-bitcoin-app-router/package.json examples/nuxt-wagmi-solana-bitcoin/package.json examples/nuxt-wagmi/package.json examples/parcel/package.json examples/react-wagmi/package.json examples/sveltekit-4-wagmi/package.json examples/sveltekit-wagmi/package.json examples/vue-wagmi-solana/package.json examples/vue-wagmi/package.json packages/adapters/wagmi/package.json packages/appkit-utils/package.json packages/appkit/exports/constants.ts packages/appkit/package.json packages/cdn/package.json packages/common/package.json packages/controllers/package.json packages/experimental/package.json packages/siwe/package.json packages/siwx/package.json pnpm-lock.yaml
Expand the set of WC HTTP RPC supported chains to include a new EVM network.	Add eip155:55931 to WC_HTTP_RPC_SUPPORTED_CHAINS so it is recognized as supported for WalletConnect HTTP RPC flows.	packages/appkit-utils/src/CaipNetworkUtil.ts

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Originally posted by @sourcery-ai[bot] in #874 (comment)