tokenBridge: fromIdentifier amount scaling fix (#700)

* tokenBridge: fromIdentifier amount scaling fix

We were not scaling the transfer amount on the VAA to the source chain
amount correctly.

Fixes #580

* fix toNative chain

connect/src/protocols/tokenBridge/tokenTransfer.ts

@@ -1,5 +1,11 @@
 import type { Chain, Network } from "@wormhole-foundation/sdk-base";
-import { amount, encoding, finality, guardians, toChain as toChainName } from "@wormhole-foundation/sdk-base";
+import {
+ amount,
+ encoding,
+ finality,
+ guardians,
+ toChain as toChainName,
+} from "@wormhole-foundation/sdk-base";
 import type {
  AttestationId,
  AutomaticTokenBridge,
@@ -167,9 +173,20 @@ export class TokenTransfer<N extends Network = Network>
  let from = { chain: vaa.emitterChain, address: vaa.emitterAddress };
  let { token, to } = vaa.payload;
 
+ let nativeAddress: NativeAddress<Chain>;
+ if (token.chain === from.chain) {
+ nativeAddress = await wh.getTokenNativeAddress(from.chain, token.chain, token.address);
+ } else {
+ const fromChain = await wh.getChain(from.chain);
+ const tb = await fromChain.getTokenBridge();
+ const wrapped = await tb.getWrappedAsset(token);
+ nativeAddress = toNative(from.chain, wrapped.toString());
+ }
+
+ const decimals = await wh.getDecimals(from.chain, nativeAddress);
  const scaledAmount = amount.scale(
- amount.fromBaseUnits(token.amount, TokenTransfer.MAX_DECIMALS),
- await wh.getDecimals(token.chain, token.address),
+ amount.fromBaseUnits(token.amount, Math.min(decimals, TokenTransfer.MAX_DECIMALS)),
+ decimals,
  );
 
  let nativeGasAmount: bigint = 0n;