implementation of EtherscanApiStatusError class for better error handling

TheDataDiver · TheDataDiver · commit 74b6ed1c22e2 · 2021-11-09T23:49:43.000Z
diff --git a/index.js b/index.js
@@ -1,6 +1,8 @@
-'use strict';
-const init = require('./lib/init');
+"use strict";
+const init = require("./lib/init");
+const EtherscanApiStatusError = require("./lib/etherscanApiStatusError");
 
 module.exports = {
-  init
+  init,
+  EtherscanApiStatusError,
 };
diff --git a/lib/etherscanApiStatusError.js b/lib/etherscanApiStatusError.js
@@ -0,0 +1,5 @@
+module.exports = class EtherscanApiStatusError {
+  constructor(message) {
+    this.message = message;
+  }
+};
diff --git a/lib/get-request.js b/lib/get-request.js
@@ -1,5 +1,6 @@
+const axios = require("axios");
+const EtherscanApiStatusError = require("./etherscanApiStatusError");
 
-const axios = require('axios');
 /**
  * @param {string} chain
  * @returns {string}
@@ -12,55 +13,60 @@ function pickChainUrl(chain) {
   return TESTNET_API_URL_MAP[chain];
 }
 
-
-const MAIN_API_URL = 'https://api.etherscan.io';
+const MAIN_API_URL = "https://api.etherscan.io";
 const TESTNET_API_URL_MAP = {
-  ropsten: 'https://api-ropsten.etherscan.io',
-  kovan: 'https://api-kovan.etherscan.io',
-  rinkeby: 'https://api-rinkeby.etherscan.io',
-  homestead: 'https://api.etherscan.io'
+  ropsten: "https://api-ropsten.etherscan.io",
+  kovan: "https://api-kovan.etherscan.io",
+  rinkeby: "https://api-rinkeby.etherscan.io",
+  homestead: "https://api.etherscan.io",
 };
 
-module.exports = function(chain, timeout) {
+// Axios automatically throws an error if statusCode is 4xx/5xx
+module.exports = function (chain, timeout) {
   var client = axios.create({
     baseURL: pickChainUrl(chain),
-    timeout: timeout
+    timeout: timeout,
   });
 
   /**
    * @param query
    * @returns {Promise<any>}
    */
   function getRequest(query) {
-    return new Promise(function(resolve, reject) {
-      client.get('/api?' + query).then(function(response) {
-        var data = response.data;
+    return new Promise(function (resolve, reject) {
+      client
+        .get("/api?" + query)
+        .then(function (response) {
+          var data = response.data;
+          if (data.status && data.status != 1) {
+            let returnMessage = data.message || "NOTOK";
+            if (
+              data.hasOwnProperty("result") &&
+              typeof data.result === "string"
+            ) {
+              returnMessage = data.result;
+            } else if (data.message && typeof data.message === "string") {
+              returnMessage = data.message;
+            }
 
-        if (data.status && data.status != 1) {
-          let returnMessage = data.message ||'NOTOK';
-          if (data.result && typeof data.result === 'string') {
-            returnMessage = data.result;
-          } else if (data.message && typeof data.message === 'string') {
-            returnMessage = data.message;
+            return reject(new EtherscanApiStatusError(returnMessage));
           }
 
-          return reject(returnMessage);
-        }
+          if (data.error) {
+            var message = data.error;
 
-        if (data.error) {
-          var message = data.error;
+            if (typeof data.error === "object" && data.error.message) {
+              message = data.error.message;
+            }
 
-          if(typeof data.error === 'object' && data.error.message){
-            message = data.error.message;
+            return reject(new Error(message));
           }
 
-          return reject(new Error(message));
-        }
-
-        resolve(data);
-      }).catch(function(error) {
-        return reject(new Error(error));
-      });
+          resolve(data);
+        })
+        .catch(function (error) {
+          return reject(new Error(error));
+        });
     });
   }
 
