refactored tokenblacklist to have less if nesting

lib/util/token-blacklist.js

@@ -2,31 +2,37 @@ const LRU = require('lru-cache')
 const consoleLogger = require('./logger.js')
 
 class TokenBlacklist {
-  constructor(eventEmitter, maxIndexingErrors, errorRegex) {
+  constructor (eventEmitter, maxIndexingErrors, errorRegex) {
     this.errorRegex = errorRegex || /Application not found for token (\S+),/
-    this.maxIndexingErrors = maxIndexingErrors || 1 // failures before blacklisting tokens 
+    this.maxIndexingErrors = maxIndexingErrors || 1 // failures before blacklisting tokens
     this.invalidTokens = new LRU({
       max: 5000,
       maxAge: 10 * 60 * 1000
     })
+
     eventEmitter.on('error', function (err) {
-      // blacklist tokens ony when the token is unknown 
-      let match = String(err).match(this.errorRegex)
-      if (match && match.length > 1) {
-        if (!this.invalidTokens.get(match[1])) {
-          this.invalidTokens.set(match[1], 1)
-        } else {
-          this.invalidTokens.set(match[1], this.invalidTokens.get(match[1]))
-        }
-        if (this.invalidTokens.get(match[1]) >= this.maxIndexingErrors) {
-          consoleLogger.log(`Invalid token added to blacklist ${match[1]}`)
-        }
+      // blacklist tokens only when the token is unknown
+      const match = String(err).match(this.errorRegex)
+      const token = match && match.length > 1 && match[1]
+      if (!token) {
+        return
+      }
+
+      if (!this.invalidTokens.get(token)) {
+        this.invalidTokens.set(token, 1)
+      } else {
+        this.invalidTokens.set(token, this.invalidTokens.get(token))
+      }
+
+      if (this.invalidTokens.get(token) >= this.maxIndexingErrors) {
+        consoleLogger.log(`Invalid token added to blacklist ${token}`)
       }
     }.bind(this))
   }
-  isTokenInvalid(token) {
+
+  isTokenInvalid (token) {
     return this.invalidTokens.get(token) >= this.maxIndexingErrors
   }
 }
 
-module.exports = TokenBlacklist
+module.exports = TokenBlacklist