Merge pull request #25 from curvefi/feat/add-getLsdApy

feat: add getLsdApy

Author: fedorovdg

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@curvefi/stablecoin-api",
-  "version": "1.5.5",
+  "version": "1.5.6",
   "description": "JavaScript library for Curve Stablecoin",
   "main": "lib/index.js",
   "author": "Macket",

src/index.ts

@@ -2,7 +2,16 @@ import { ethers } from "ethers";
 import { Networkish } from "@ethersproject/networks";
 import { LlammaTemplate, getLlamma } from "./llammas";
 import { crvusd as _crvusd } from "./crvusd";
-import { getBalances, getAllowance, hasAllowance, ensureAllowanceEstimateGas, ensureAllowance, getUsdRate, totalSupply } from "./utils";
+import {
+    getBalances,
+    getAllowance,
+    hasAllowance,
+    ensureAllowanceEstimateGas,
+    ensureAllowance,
+    getUsdRate,
+    totalSupply,
+    getLsdApy,
+} from "./utils";
 
 
 async function init (
@@ -34,6 +43,7 @@ const crvusd = {
     ensureAllowance,
     getUsdRate,
     totalSupply,
+    getLsdApy,
     getLlammaList: _crvusd.getLlammaList,
     estimateGas: {
         ensureAllowance: ensureAllowanceEstimateGas,

src/utils.ts

@@ -4,6 +4,7 @@ import BigNumber from 'bignumber.js';
 import { IDict } from "./interfaces";
 import { _getPoolsFromApi } from "./external-api";
 import { crvusd } from "./crvusd";
+import memoize from "memoizee";
 
 export const MAX_ALLOWANCE = ethers.BigNumber.from(2).pow(ethers.BigNumber.from(256)).sub(ethers.BigNumber.from(1));
 export const MAX_ACTIVE_BAND = ethers.BigNumber.from(2).pow(ethers.BigNumber.from(255)).sub(ethers.BigNumber.from(1));
@@ -288,4 +289,48 @@ export const totalSupply = async (): Promise<{ total: string, minted: string, pe
     }
 
     return { total: mintedBN.plus(pegKeepersBN).toString(), minted: mintedBN.toString(), pegKeepersDebt: pegKeepersBN.toString() };
-}
+}
+
+export const getLsdApy = memoize(async(name: 'wstETH' | 'sfrxETH'): Promise<{
+        apy: number,
+        baseApy: number,
+        apyMean30d: number,
+    }> => {
+    const response = await axios.get('https://yields.llama.fi/pools');
+    const {data} = response.data;
+
+    const params = {
+        'wstETH': {
+            project: 'lido',
+            symbol: 'STETH',
+        },
+        'sfrxETH': {
+            project: 'frax-ether',
+            symbol: 'SFRXETH',
+        },
+    }
+
+    const result = data.find(({
+        chain,
+        project,
+        symbol,
+    }: any) => (
+        chain === 'Ethereum' &&
+        project === params[name].project &&
+        symbol === params[name].symbol
+    ));
+
+    if(result) {
+        return {
+            apy: result.apy,
+            baseApy: result.apyBase,
+            apyMean30d: result.apyMean30d,
+        };
+    }
+
+    throw new Error('Pool not found')
+},
+{
+    promise: true,
+    maxAge: 60 * 1000, // 1m
+});