refactor and lint

packages/financial-templates-lib/src/price-feed/DefiPulseTotalPriceFeed.js

@@ -1,5 +1,4 @@
 const { PriceFeedInterface } = require("./PriceFeedInterface");
-const { parseFixed } = require("@ethersproject/bignumber");
 const assert = require("assert");
 
 // An implementation of PriceFeedInterface that uses DefiPulse Data api to retrieve prices.
@@ -15,7 +14,7 @@ class DefiPulseTotalPriceFeed extends PriceFeedInterface {
    * @param {Integer} minTimeBetweenUpdates Min number of seconds between updates. If update() is called again before
    *      this number of seconds has passed, it will be a no-op.
    */
-  constructor(logger, web3, apiKey, lookback, networker, getTime, minTimeBetweenUpdates, decimals = 18) {
+  constructor(logger, web3, apiKey, lookback, networker, getTime, minTimeBetweenUpdates) {
     super();
     this.logger = logger;
     this.web3 = web3;
@@ -28,7 +27,7 @@ class DefiPulseTotalPriceFeed extends PriceFeedInterface {
     this.getTime = getTime;
     this.minTimeBetweenUpdates = minTimeBetweenUpdates;
 
-    this.toBN = this.web3.utils.toBN;
+    this.toWei = this.web3.utils.toWei;
 
     this.historicalPrices = [];
   }
@@ -44,7 +43,7 @@ class DefiPulseTotalPriceFeed extends PriceFeedInterface {
 
     let closestTime = { timestamp: 0, tvlUSD: 0 };
 
-    // go through all values and find time that that is the largest and still less than 'time'
+    // Go through all values and find time that that is the largest and still less than 'time'
     for (let i = 0; i < this.historicalPrices.length; i++) {
       let past = this.historicalPrices[i].timestamp;
       let val = this.historicalPrices[i].tvlUSD;
@@ -55,12 +54,12 @@ class DefiPulseTotalPriceFeed extends PriceFeedInterface {
       }
     }
 
-    const historicalPrice = this.web3.utils.toWei((closestTime.tvlUSD / 1000000000).toFixed(3), "ether");
+    const historicalPrice = this.scaleResult(closestTime.tvlUSD);
 
     if (closestTime.timestamp === 0) {
       return undefined;
     } else {
-      return this.toBN(historicalPrice);
+      return historicalPrice;
     }
   }
 
@@ -124,16 +123,21 @@ class DefiPulseTotalPriceFeed extends PriceFeedInterface {
       }
     }
 
-    // Based on the UMIP 24
-    // newPrice = Sum of TVL for all projects on DeFi Pulse divided by 1,000,000,000 with 3 decimal points of precision
-
-    const newPrice = this.web3.utils.toWei((mostRecent.tvlUSD / 1000000000).toFixed(3), "ether");
+    const newPrice = this.scaleResult(mostRecent.tvlUSD);
 
     // 5. Store results.
     this.lastUpdateTime = currentTime;
-    this.currentPrice = this.toBN(newPrice);
+    this.currentPrice = newPrice;
     this.historicalPrices = response;
   }
+
+  scaleResult(_tvlUSD) {
+    // As described in UMIP 24
+    // In an effort to make the token price affordable, the value of the token is the tvlUSD divided by 1 billion.
+    // We also cut off precision after 3 decimals to match the specified price step of .001
+
+    return this.toWei((_tvlUSD / 1000000000).toFixed(3), "ether");
+  }
 }
 
 module.exports = {