use of es6, pipeline and concat-stream

exercises/reduce/solution/solution.js

@@ -1,20 +1,28 @@
-var http = require('http')
-  , async = require('async');
+"use strict";
+const { get } = require("http");
+const async = require("async");
+const { pipeline } = require("stream");
+const concat = require("concat-stream");
 
-async.reduce(['one', 'two', 'three'], 0, function(memo, item, done){
-  var body = '';
-
-  http.get(process.argv[2] + "?number=" + item, function(res){
-    res.on('data', function(chunk){
-      body += chunk.toString();
-    });
-
-    res.on('end', function(){
-      done(null, memo + Number(body));
-    });
-  }).on('error', done);
-
-}, function done(err, result){
-  if (err) return console.log(err);
-  console.log(result);
-});
+async.reduce(
+  ["one", "two", "three"],
+  0,
+  function (memo, item, done) {
+    get(process.argv[2] + "?number=" + item, (res) => {
+      res.setEncoding("utf-8");
+      pipeline(
+        res,
+        concat((data) => {
+          done(null, Number(data) + memo);
+        }),
+        (err) => {
+          if (err) return done(err);
+        }
+      );
+    }).on("error", done);
+  },
+  function (err, result) {
+    if (err) return console.error(err);
+    console.log(result);
+  }
+);