Remove Node.js v8 support (#1402)

index.js

@@ -27,8 +27,7 @@ const debug = require('debug')('elasticsearch')
 const Transport = require('./lib/Transport')
 const Connection = require('./lib/Connection')
 const { ConnectionPool, CloudConnectionPool } = require('./lib/pool')
-// Helpers works only in Node.js >= 10
-const Helpers = nodeMajor < 10 ? /* istanbul ignore next */ null : require('./lib/Helpers')
+const Helpers = require('./lib/Helpers')
 const Serializer = require('./lib/Serializer')
 const errors = require('./lib/errors')
 const { ConfigurationError } = errors
@@ -48,15 +47,6 @@ const kEventEmitter = Symbol('elasticsearchjs-event-emitter')
 
 const ESAPI = require('./api')
 
-/* istanbul ignore next */
-if (nodeMajor < 10) {
-  process.emitWarning('You are using a version of Node.js that is currently in EOL. ' +
-                      'The support for this version will be dropped in 7.12. ' +
-                      'Please refer to https://ela.st/nodejs-support for additional information.',
-  'DeprecationWarning'
-  )
-}
-
 /* istanbul ignore next */
 if (nodeMajor >= 10 && nodeMajor < 12) {
   process.emitWarning('You are using a version of Node.js that will reach EOL in April 2021. ' +
@@ -189,16 +179,13 @@ class Client extends ESAPI {
       context: options.context
     })
 
-    /* istanbul ignore else */
-    if (Helpers !== null) {
-      this.helpers = new Helpers({
-        client: this,
-        maxRetries: options.maxRetries,
-        metaHeader: options.enableMetaHeader
-          ? `es=${clientVersion},js=${nodeVersion},t=${clientVersion},hc=${nodeVersion}`
-          : null
-      })
-    }
+    this.helpers = new Helpers({
+      client: this,
+      maxRetries: options.maxRetries,
+      metaHeader: options.enableMetaHeader
+        ? `es=${clientVersion},js=${nodeVersion},t=${clientVersion},hc=${nodeVersion}`
+        : null
+    })
   }
 
   get emit () {
@@ -223,7 +210,7 @@ class Client extends ESAPI {
       opts = {}
     }
 
-    var [namespace, method] = name.split('.')
+    let [namespace, method] = name.split('.')
     if (method == null) {
       method = namespace
       namespace = null