From 4373641a30fe9f4fbddcec1082146d88ffda0b57 Mon Sep 17 00:00:00 2001
From: Danil Kovtonyuk <danx.kov@gmail.com>
Date: Tue, 16 Nov 2021 03:40:08 +1000
Subject: [PATCH] fix: normalize result values

---
 package.json        |  2 +-
 src/index.ts        | 31 ++++++++++++------------
 tests/index.test.ts | 58 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+), 16 deletions(-)

diff --git a/package.json b/package.json
index 4c5451b..68e3927 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "gas-price-oracle",
-  "version": "0.4.3",
+  "version": "0.4.4",
   "description": "Gas Price Oracle library for Ethereum dApps.",
   "main": "lib/index.js",
   "homepage": "https://github.com/peppersec/gas-price-oracle",
diff --git a/src/index.ts b/src/index.ts
index e28ce51..4100a35 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -36,6 +36,8 @@ export class GasPriceOracle {
       Object.assign(this.configuration, options);
     }
 
+    this.configuration.defaultFallbackGasPrices = this.normalize(this.configuration.defaultFallbackGasPrices);
+
     const network = NETWORKS[this.configuration.chainId];
 
     if (network) {
@@ -225,38 +227,37 @@ export class GasPriceOracle {
           : await this.fetchGasPricesOffChain();
         return this.lastGasPrice;
       } catch (e) {
-        console.log('Failed to fetch gas prices from offchain oracles. Trying onchain ones...');
+        console.log('Failed to fetch gas prices from offchain oracles...');
       }
     }
 
     if (Object.keys(this.onChainOracles).length > 0) {
       try {
         const fastGas = await this.fetchGasPricesOnChain();
-        this.lastGasPrice = {
-          instant: fastGas * 1.3,
-          fast: fastGas,
-          standard: fastGas * 0.85,
-          low: fastGas * 0.5,
-        };
+        this.lastGasPrice = this.categorize(fastGas);
         return this.lastGasPrice;
       } catch (e) {
-        console.log('Failed to fetch gas prices from onchain oracles. Trying from default RPC...');
+        console.log('Failed to fetch gas prices from onchain oracles...');
       }
     }
 
     try {
       const fastGas = await this.fetchGasPriceFromRpc();
-      this.lastGasPrice = {
-        instant: fastGas * 1.3,
-        fast: fastGas,
-        standard: fastGas * 0.85,
-        low: fastGas * 0.5,
-      };
+      this.lastGasPrice = this.categorize(fastGas);
       return this.lastGasPrice;
     } catch (e) {
       console.log('Failed to fetch gas prices from default RPC. Last known gas will be returned');
     }
-    return this.lastGasPrice;
+    return this.normalize(this.lastGasPrice);
+  }
+
+  categorize(gasPrice: number): GasPrice {
+    return this.normalize({
+      instant: gasPrice * 1.3,
+      fast: gasPrice,
+      standard: gasPrice * 0.85,
+      low: gasPrice * 0.5,
+    });
   }
 
   addOffChainOracle(oracle: OffChainOracle): void {
diff --git a/tests/index.test.ts b/tests/index.test.ts
index d532524..d5e1776 100644
--- a/tests/index.test.ts
+++ b/tests/index.test.ts
@@ -2,6 +2,7 @@
 /* eslint-disable @typescript-eslint/no-var-requires */
 import chai from 'chai';
 import mockery from 'mockery';
+import BigNumber from 'bignumber.js';
 
 import { ChainId, NETWORKS } from '../src/config';
 import { GasPriceOracle } from '../src/index';
@@ -240,6 +241,63 @@ describe('fetchMedianGasPriceOffChain', function () {
   });
 });
 
+describe('normalize result values', function () {
+  const wrongDecimalsGas = {
+    instant: 1.1,
+    fast: 2.12345678901,
+    standard: 3.12345678901,
+    low: 3.1234567890123456789,
+  };
+
+  const checkDecimals = (gas: GasPrice) => {
+    const gasPrices: number[] = Object.values(gas);
+
+    for (const gas of gasPrices) {
+      new BigNumber(gas).dp().should.be.at.most(9);
+    }
+  };
+
+  it('default fallback should be normalized', function () {
+    mockery.enable({ useCleanCache: true, warnOnUnregistered: false });
+
+    const { GasPriceOracle } = require('../src/index');
+    oracle = new GasPriceOracle({
+      defaultFallbackGasPrices: wrongDecimalsGas,
+    });
+    const { configuration } = oracle;
+
+    checkDecimals(configuration.defaultFallbackGasPrices);
+
+    mockery.disable();
+  });
+
+  it('fallback should be normalized', async function () {
+    mockery.enable({ useCleanCache: true, warnOnUnregistered: false });
+
+    const { GasPriceOracle } = require('../src/index');
+    oracle = new GasPriceOracle();
+
+    const gas = await oracle.gasPrices(wrongDecimalsGas);
+
+    checkDecimals(gas);
+    mockery.disable();
+  });
+
+  it('rpc fallback should be normalized', async function () {
+    const { GasPriceOracle } = require('../src/index');
+    oracle = new GasPriceOracle({ chainId: ChainId.ARBITRUM, defaultRpc: 'https://arb1.arbitrum.io/rpc' });
+
+    const { onChainOracles, offChainOracles } = oracle;
+
+    Object.keys(onChainOracles).forEach(chainOracle => oracle.removeOnChainOracle(chainOracle));
+    Object.keys(offChainOracles).forEach(chainOracle => oracle.removeOffChainOracle(chainOracle));
+
+    const gas = await oracle.gasPrices();
+
+    checkDecimals(gas);
+  });
+});
+
 describe('askOracle', function () {
   const chains = Object.keys(NETWORKS).map(id => Number(id));