Merge pull request #655 from interlay/peter/fix-qtoken-exchange-rate

Peter/fix qtoken exchange rate

package.json

@@ -1,6 +1,6 @@
 {
  "name": "@interlay/interbtc-api",
- "version": "2.3.5",
+ "version": "2.3.6",
  "description": "JavaScript library to interact with interBTC",
  "main": "build/src/index.js",
  "typings": "build/src/index.d.ts",

src/parachain/oracle.ts

@@ -101,14 +101,23 @@ export class DefaultOracleAPI implements OracleAPI {
 
  if (isLendToken(currency)) {
  const lendTokenId = newCurrencyId(this.api, currency);
- const underlyingCcyId = await this.api.query.loans.underlyingAssetId(lendTokenId);
-
- const rawLendToUnderlying = (await this.api.query.loans.exchangeRate(underlyingCcyId)) as UnsignedFixedPoint;
+ const underlyingCurrencyIdRaw = await this.api.query.loans.underlyingAssetId(lendTokenId);
+ if (underlyingCurrencyIdRaw.isNone) {
+ throw new Error(
+ `No underlying asset found for lend token with id ${lendTokenId.asLendToken.toString()}`
+ );
+ }
+ const underlyingCurrencyId = underlyingCurrencyIdRaw.unwrap();
+
+ const rawLendToUnderlying = await this.api.query.loans.exchangeRate(underlyingCurrencyId);
+
  // multiply this rate with lendtoken to get underlying amount
  const lendToUnderRate = decodeFixedPointType(rawLendToUnderlying);
-
- const underlyingCurrency = await currencyIdToMonetaryCurrency(this.api, underlyingCcyId.unwrap());
- const btcToUnderRate = (await this.convertWrappedToCurrency(new MonetaryAmount(Bitcoin, 1), underlyingCurrency)).toBig();
+
+ const underlyingCurrency = await currencyIdToMonetaryCurrency(this.api, underlyingCurrencyIdRaw.unwrap());
+ const btcToUnderRate = (
+ await this.convertWrappedToCurrency(new MonetaryAmount(Bitcoin, 1), underlyingCurrency)
+ ).toBig();
  const btcToLendRate = btcToUnderRate.div(lendToUnderRate);
 
  // final rate is normalized (base unit vs base unit), construct accordingly